Cannabidiol (CBD) is one of over 80 active cannabinoids found in Cannabis Sativa and is the second most abundant cannabinoid derived from the plant following d(9)-Tetrahydrocannabinol (THC). As opposed to THC, CBD does not appear to have any psychotropic effects, rather CBD is often utilized for its therapeutic properties, which include effects such as antinociception, anti-convulsion, and anti-inflammation. During the extraction of CBD from plant material, THC may be co-extracted. Therefore, screening and quantitating potential THC levels in individuals using CBD products is important in instances where the legality of use of THC does not match that of CBD. In recent years, oral fluid has gained recognition as a non-invasive and expedient matrix for both drug testing and forensic casework. Due to its relevance, oral fluid was selected for analysis. This project evaluated the detection and quantitation of CBD, THC, and two primary metabolites in oral fluid samples of a therapeutic-use cannabidiol donor using Biotage Supported Liquid Extraction (SLE) and subsequent testing by PerkinElmer QSight 220 CR LC-MS/MS in positive ionization mode All calibrators and quality controls were prepared by fortifying synthetic oral fluid with certified reference standards. Standards and samples were prepared in a 1:3 dilution with extraction buffer. Calibrators were prepared at 0.25, 0.5, 1, 5, 10, 50, 100, 200, 300, 400, and 500 ng/mL, with quality controls analyzed at 0.75, 70, and 425 ng/mL. Internal standard was added to the appropriate samples to account for any variation produced by sample preparation. SLE was performed using ISOLUTE SLE+ 1 mL columns with elution in hexane:ethyl acetate:methyl tert-butyl ether (80:10:10), followed by evaporation using an Organomation Multivap Nitrogen Evaporator (Berlin, Massachusetts). All samples were reconstituted in 100 uL of 0.1% formic acid in deionized water:0.1% formic acid in acetonitrile (70:30). Validation parameters were assessed using Academy Standards Board (ASB) Standard 036-Standard Practices for Method Validation in Forensic Toxicology, including linear dynamic range (LDR), limit of detection (LOD), limit of quantitation (LOQ), analyte recovery, ion suppression/enhancement, and carryover. Following reconstitution, samples were placed onto the autosampler for injection and subsequent chromatographic separation using a PerkinElmer Brownlee C18 2.1x50 millimeter (mm), 2.7 micrometer (um) column. Analysis of the samples by mass spectrometry was performed in positive mode with multiple reaction monitoring (MRM). Total run time including equilibration was 10.5 minutes. All compounds were quantified using linear calibration models with 1/X weighting (1/concentration) and measured values were normalized by their respective internal standards. The LDR was determined to be 0.25 to 500 ng/mL. For all analytes, LOD was assessed and determined to be 0.25 ng/mL with an LOQ of 1 ng/mL. Carryover was assessed by running a double blank following a sample spiked at 500 ng/mL with no analytes observed. The donor samples were collected at several timepoints around the oral administration of an 8 mg dose of CBD. These timepoints included: prior to administration, at the time of administration, 30 minutes post-administration, 45 minutes post-administration, 60 minutes post-administration, 90 minutes post-administration, and 120 minutes post-administration. CBD was quantified within the diluted oral fluid samples from below LOQ to 325.75 ng/mL. THC was detected above LOD but below LOQ, concentrations which lie below typical cut-offs used in both workplace drug testing and forensic casework. The two metabolites were not detected above the LOD. As such, the CBD product can be concluded to be of reasonable purity as it relates to legal implications. Overall, the use of laminar flow mass spectrometry was effective in detecting various cannabinoids in oral fluid samples following SLE sample extraction.

Stockholm står inför en historisk befolkningstillväxt och nu väntas en tid av ombyggnationer och förtätningar av Stockholms storstadsregion. Denna utveckling bidrar starkt till att även CBD växer. Det finns ett flertal projekt som pågår eller planeras i CBD. Ett av dessa projekt är totalrenoveringen av Diligentias profilfastighet Sveavägen 44 i utkanten av norra CBD. Tidigare har det funnits andra projekt som genomförts i utkanten av CBD. I Centralenområdet genomfördes ett flertal stora projekt. På Blasieholmen genomfördes en satsning på tre fastigheter. Dessa projekt har varit lyckade i avseende på sin områdespåverkan och har mer eller mindre varit startskott för en större fastighetsutveckling i områdena. Båda områdena är en del av det vi idag kallar CBD. Detta examensarbete syftar till att utreda om och i så fall, hur stor, påverkan Sveavägen 44 har på närområdet. Än så länge är Sveavägen 44 ganska isolerat från city och ensamt i sin klass. Frågan är om Diligentias investering i Sveavägen 44 kan locka fler aktörer i området att förädla sina fastigheter och att dessa projekt i slutändan får ett stort genomslag. Utvecklingen av norra CBD kommer att diskuteras i avseende på områdesutveckling, hyresutveckling, värdeutveckling och vakans. Slutsatsen av studien är att effekterna från Sveavägen 44 är positiva men begränsade i utsträckning då området som helhet har haft få effekter. Den största effekt Sveavägen 44 har haft på området i norra CBD är hyrespåverkan. I takt med att hyror i CBD har ökat har det faktum att Diligentia kräver hyror högt över medelhyran i området bidragit till en stark positiv hyresutveckling i området. Attraktiviten för butiks- och kontorslokaler i området har ökat, framförallt för de förstnämnda. Butiker i området står förmodligen för en större utveckling framöver; den ökade efterfrågan kommer med sannolikhet tvinga utbudet till en upprustning. Förutom förädlingen för butikslokaler bedöms områdesutvecklingen annars stå stilla. Fastigheternas låga ytvakans och relativt höga standard håller tillbaka en större fastighetsutveckling i området. Möjligtvis kommer mindre flexibla fastigheter med rumsindelade lokaler, som nu har höga vakanser, att konverteras till bostäder. Områdets status som Stockholms China Town, om än svagt idag, kommer att blekna och området längre norrut längs Sveavägen, utanför CBD, kommer befästas som Stockholms China Town. / Stockholm has a historical population growth and a time of reconstruction and densification is to be expected for the metropolitan area of Stockholm. This change contributes strongly to extension of the CBD. There are many projects under construction or in the planning process in city. One of these projects is the refurbishment of Diligentia’s profile property Sveavägen 44 in the northern parts of the CBD. There have been projects implemented in the outskirts of CBD before. In the Central Station area a number of large projects have been carried out. At Blasieholmen there was a big investment in three properties. These projects have been successful in terms of its impact on the area and they have more or less been a starting point for a larger real estate development in its area. Both areas are part of what is today considered as CBD. This master thesis aims to investigate whether, and if so, how much impact the renovation of Sveavägen 44 has on the surrounding area. So far, Sveavägen 44 is relatively isolated from the city center and alone of its high standard in the area. The question is if Diligentia’s large investment in Sveavägen 44 could motivate more players in the area to refine their properties and these projects will end up having a big impact on the area. The development of the northern CBD will be discussed in terms of area development, rental development, value creation and the vacancy rate. The conclusion of the study is that the impact Sveavägen 44 has on the area is positive but limited in the extent to which the area as a whole has had an impact. The biggest impact on the area in northern CBD Sveavägen 44 has had is on the rental development. In line with the increased rental levels in CBD, together with the fact that Diligentia is demanding rents over the average rental level for the area, has contributed to a strong positive rental development. The demands for retail and office space in the area have increased, especially for the former. Shops in the area are facing a larger development in the future; the increased demand will likely compel supply improvement. Besides the refinement of retail premises the development of the area is assessed to otherwise stand still. The low vacancy rate of space and relatively high standard for the properties in the area will hold back a movement of upgrading the premises. It is possible for the difficult room structured properties, suffering from high vacancies, to be converted into residential. The status of the area as Stockholm’s China Town, yet not widely used, will fade and an area further north alongside Sveavägen, outside the border of CBD, will be consolidated as Stockholm’s China Town.

No description available.

Yes / Although batch reactive distillation process outperforms traditional reactor-distillation processes due to simultaneous reaction and separation of products for many reaction systems, synthesis of Methyl lactate (ML) through esterification of lactic acid (LA) with methanol in such process is very challenging due to difficulty of keeping the reactants together when one of the reactants (in this case methanol) has the lowest boiling point than the reaction products. To overcome this challenge, two novel reactive distillation column configurations are proposed in this work and are investigated in detail. These are: (1) integrated conventional batch distillation column (i-CBD) with recycled methanol and (2) integrated semi-batch and conventional batch distillation columns (i-SBD) with methanol recovery and recycle. Performances of each of these configurations are evaluated in terms of profitability for a defined separation task. In i-SBD column, an additional constraint is included to avoid overflow of the reboiler due to continuous feeding of methanol into the reboiler as the reboiler is initially charged to its maximum capacity. This study clearly indicates that both integrated column configurations outperform the traditional column configurations (batch or semi-batch) in terms of batch time, energy consumption, conversion of LA to ML, and the achievable profit.

No description available.

The overall purpose of this paper was to critically analyze the legal prerequisites for using medical cannabis in Sweden. The legal method and the legal analysis method have been the basis for the analysis of current law, regarding medical use of cannabis and drug abuse. Current law has been analyzed led by a medical approach to clarify the legal and medical meaning of drug abuse. The Narcotic Drugs Punishment Act makes no distinction between drug abuse and medical use, which means that all forms of use ending up in a drug offence. It ́s not obvious what constitutes narcotics because the cannabis plant is divided into different species and it ́s also available in various forms of preparations. Against this background, the medical usage of cannabis seems to have ended up in a legal grey zone. The cannabis preparation called Bediol includes whole plant parts of cannabis and is treated as drug abuse according to the law, but regarding the legal view of CBD-extract the position is more unclear. The prevailing opinion in law cases of today is that CBD-extracts do not constitute drugs. The question of cannabis for self-medication has been pointed in NJA 2017 s. 872, the Supreme Court considers that the medical motive mitigates the crime classification and that a medical purpose can cause a situation of emer- gency. It ́s still unclear how the prerequisites “addictive properties” and ”euphoric effects” in paragraph 8 in the Narcotic Drugs Punishment Act shall be read regarding the occasion of medical use. As long as cannabis is under extensive international control the uncertainty remains about how the prerequisites in paragraph 8 in the Narcotic Drugs Punishment Act should be treated in relative to the medical motive. Furthermore, the study based on the Swedish Medical Products Agency’s decision regarding Bediol and Epidiolex shows that the Medical Products Agency has a tolerant attitude towards both cannabis preparations. The study of license decisions has also been relevant to clarify the discrepancy between medical use and how it ́s considered according to the Narcotic Drugs Punishment Act. The study demonstrates how the Swedish Medical Products Agency's attitude does not always interact with the view of the law. Since the decisions about licenses can be seen as an exception to the Narcotic Drugs Punishment Act, there should be some sort of consensus in how the preparations should be viewed from an authority and law point of view. This to not affect the predictability of a drug abuse in respect of the Narcotic Drugs Punishment Act. As the Medical Products Agency considers both the medical rudiments and the medical development this should be taken into account in the Narcotic Drugs Punishment Act in a more extensive way, to reach some sort of consensus. The national law can only be changed in a sharpening direction, which means that a future international reclassification of cannabis may be considered as a guide in how much space the medical motives can be applied in the 8 paragraph in the Narcotic Drugs Punishments Act. / Det övergripande syftet med denna uppsats var att kritiskt analysera de legala förutsättningarna för att använda medicinsk cannabis i Sverige. I uppsatsen har den rättsdogmatiska och rättsanalytiska metoden legat till grund för analysen av gällande rätt avseende medicinskt bruk av cannabis samt narkotikamissbruk. Gällande rätt har till viss del analyserats med ledning av en medicinsk infallsvinkel för att tydliggöra den juridiska och medicinska innebörden av narkoti- kamissbruk. Narkotikastrafflagen gör ingen skillnad på narkotikamissbruk och medicinskt bruk, vilket resulterar i att alla former av bruk innebär ett narkotikabrott. Då cannabisplantan är uppdelad i olika arter och att cannabis finns tillgängligt i olika former av preparat, blir det inte helt självklart vad som utgör narkotika. Mot denna bakgrund tycks det medicinska bruket hamnat i en rättslig gråzon. Preparatet Bediol består av hela cannabisväxtdelar och utgör narkotika i lagens mening men vad gäller CBD-extrakt är rättsläget mer oklart. Rådande uppfattning i rättspraxis är dock att CBD-extrakt inte utgör narkotika. Frågan om cannabis i självmedicineringssyfte har behandlats i NJA 2017 s. 872 där Högsta domstolen beaktade det medicinska motivet genom mildare brottsrubricering och att ett medicinskt syfte kan föranleda en nödsituation. Det kvarstår dock oklarhet huruvida rekvisiten ”beroendeframkallande egenskaper” och euforise- rande effekter” i 8 § narkotikastrafflagen ska beaktas i fråga om ett medicinskt bruk. Så länge cannabis står under omfattande internationell kontroll kvarstår oklarheten vilken tyngd de medicinska motiven bör tillmätas vid tolkning och tillämpning av 8 §. Vidare visar den studie som gjorts beträffande Läkemedelsverkets beslut rörande Bediol och Epidiolex att verket har en tolerant inställning gentemot båda preparaten. Studien som gjorts av licensbesluten har även varit relevant för att tydliggöra diskrepansen som råder mellan medicinskt bruk och hur det betraktas enligt narkotikastrafflagen. Studien påvisar således hur verkets inställning inte alltid samverkar med den straffrättsliga synen. Eftersom licensbesluten kan ses som ett undantag från narkotikastrafflagen bör det finnas någon form av samsyn hur preparaten betraktas ur myndighets respektive straffrättslig synvinkel. Detta för att inte påverka förutsebarheten av vad ett missbruk enligt narkotikastrafflagen innebär. Då Läkemedelsverket beaktar den medicinska grunden i takt med den medicinska utvecklingen bör det för samsynens skull vara relevant att den medicinska potentialen beaktas i större utsträckning även vid tillämpning av narkotikastrafflagen. Nationell lag kan enbart utformas i skärpande riktning, vilket medför att en internationell framtida omklassificering av cannabis får anses vägledande för hur stort utrymme de medicinska motiven kan tillmätas vid tillämpning av 8 §.

No description available.

Det har alltid funnits tomma och outhyrda lokaler i Stockholm. Vakanser är något som alltid har funnits, och därför också känns som ett ständigt aktuellt ämne. Fastighetsföretag har alltid försökt se till att så mycket som möjligt av lokalerna är uthyrda, men vilka strategier finns och används vid frågor om vakans? Studien undersöker vad som sägs på marknaden i Stockholm. Med hjälp av intervjuer av ansvariga inom detta ämne hos olika kommersiella fastighetsföretag har en bild med tankar och åsikter från dessa personer målats upp för att få en inblick i vad som är viktigt att tänka på när det gäller vakanser. En enkät har också skickats ut för att få en bredare uppfattning hur de kommersiella fastighetsföretagen agerar i olika situationer, vilken strategi kring vakanser de har. Företagen har samma åsikt om hel del frågor. De är överrens om att det finns mycket pengar att tjäna genom att se till att den nuvarande hyresgästen sitter kvar i lokalen. Att få in en ny hyresgäst i lokalen går inte att göra på en dag. Det kan ta månader innan den nya hyresgästen är på plats, och vakanser är lika med förlorade pengar. Det är därför viktigt att ha en bra relation med sin hyresgäst. De frågor som ställdes som fick olika svar var bland annat hur företagen agerar för att påverka antalet lediga lokaler, vad som görs vid uppsägning av kontrakt, vad man tycker om hyresgästrepresentanter, hur de ser på ett eventuellt priskrig, varför man inte har 100 % uthyrda lokaler, hur man ser på dold vakans och vilka lokaler som är mest efterfrågade i Stockholm, På de flesta frågor har en klar majoritet av uthyrarna samma åsikt. Ingen uthyrare ger några stora rabatter till hyresgästerna. Uthyrarna vet att det är dyrt att flytta. Det finns heller inget som tyder på att en uthyrare skulle sänka sina priser bara för att en konkurrent gör det, och på sätt hamna i ett priskrig. De flesta uthyrare tycker det är skönare att förhandla direkt med hyresgästen istället för att gå genom en hyresgästrepresentant. Vilka parametrar som är viktigast i en lokal, får många olika svar i undersökningen. Nya lokaler och möjlighet att skapa rum och ny planlösning är de populäraste svaren. Få företag oroar sig för att det ska bli en högre vakansgrad i närmaste framtiden. De flesta tror att marknaden kommer vara oförändrad. / There have always been empty and vacant premises in Stockholm. Vacant space is something that has always existed, and therefore feels like a recurring topic. Property companies has always tried to ensure that as much as possible of the premises are leased, but what strategies are in place in the issues of vacancy? The study examines what is said in the market in Stockholm. Using interviews of people responsible in this line of work from various commercial real estate companies, by studying and analyzing thoughts and opinions of what these people have to say get a glimpse of what's important to think about in terms of vacancies. A survey was also sent out to get a wider understanding of how the commercial real estate firms act in different situations, the strategy around the vacancies they have. Companies have the same opinion on many questions. They agreed that there is much money to be made by ensuring that the current tenant remains in the premises. Getting a new tenant into the premises can´t be done in a day. It can take months before the new tenant is in place, and vacancies mean lost money. It is therefore important to have a good relationship with his tenant. On most issues, a clear majority of the property companies have the same opinion. No company provides big discounts. They know it's expensive to move. There is also no evidence to suggest that a company would lower their prices just because a competitor does, and end up in a price war. Most companies find it more comfortable to negotiate directly with the tenant instead of going through a tenant representative. The answers differ on what parameters are most important in an office space. The most popular answers are new spaces and the ability to make a new floor plan Very few companies worry about if there will be a higher vacancy rate in the near future. Most believe that the market will remain unchanged.

This thesis describes the development of a fast rate method for the deposition of high quality CdS and CdTe thin films. The technique uses Pulsed DC Magnetron Sputtering (PDCMS). Surprisingly, the technique produces highly stable process conditions. CREST is the first laboratory worldwide to show that pulsed DC power may be used to deposit CdS and CdTe thin films. This is a very promising process technology with potential for eventual industrial deployment. The major advantage is that the process produces high deposition rates suitable for use in solar module manufacturing. These rates are over an order of magnitude faster than those obtained by RF sputtering. In common with other applications it has also been found that the energetics of the pulsed DC process produce excellent thin film properties and the power supply configuration avoids the need for complex matching circuits. Conventional deposition methodologies for CdS, Chemical Bath Deposition (CBD) and CdTe thin films, Electrodeposition (ED), have been chosen as baselines to compare film properties with Pulsed DC Magnetron Sputtering (PDCMS). One of the issues encountered with the deposition of CdS thin films (window layers) was the presence of pinholes. A Plasma cleaning process of FTO-coated glass prior to the deposition of the CdS/CdTe solar cell has been developed. It strongly modifies and activates the TCO surface, and improves the density and compactness of the deposited CdS thin film. This, in turn, improves the optical and morphological properties of the deposited CdS thin films, resulting in a higher refractive index. The pinhole removal and the increased density allows the use of a much thinner CdS layer, and this reduces absorption of blue spectrum photons and thereby increases the photocurrent and the efficiency of the thin film CdTe cell. Replacing the conventional magnetic stirrer with an ultrasonic probe in the chemical bath (sonoCBD) was found to result in CdS films with higher optical density, higher refractive index, pinhole and void-free, more compact and uniform along the surface and through the thickness of the deposited material. PDCMS at 150 kHz, 500 W, 2.5 μs, 2 s, results in a highly stable process with no plasma arcing. It allows close control of film thickness using time only. The CdS films exhibited a high level of texture in the <001> direction. The grain size was typically ~50 nm. Pinholes and voids could be avoided by reducing the working gas pressure using gas flows ii below 20 sccm. The deposition rate was measured to be 1.33 nm/s on a rotating substrate holder. The equivalent deposition rate for a static substrate is 8.66 nm/s, which is high and much faster than can be achieved using a chemical bath deposition or RF magnetron sputtering. The transmission of CdS can be improved by engineering the band gap of the CdS layer. It has been shown that by adding oxygen to the working gas pressure in an RF sputtering deposition process it is possible to deposit an oxygenated CdS (CdS:O) layer with an improved band gap. In this thesis, oxygenated CdS films for CdTe TF-PV applications have been successfully deposited by using pulsed DC magnetron sputtering. The process is highly stable using a pulse frequency of 150 kHz and a 2.5 μs pulse reverse time. No plasma arcing was detected. A range of CdS:O films were deposited by using O2 flows from 1 sccm to 10 sccm during the deposition process. The deposition rates achieved using pulsed DC magnetron sputtering with only 500 W of power to the magnetron target were in the range ~1.49 nm/s ~2.44 nm/s, depending on the oxygen flow rate used. The properties of CdS thin films deposited by pulsed DC magnetron sputtering and chemical bath deposition have been studied and compared. The pulsed DC magnetron sputtering process produced CdS thin films with the preferred hexagonal <001> oriented crystalline structure with a columnar grain growth, while sonoCBD deposited films were polycrystalline with a cubic structure and small grainy crystallites throughout the thickness of the films. Examination of the PDCMS deposited CdS films confirmed the increased grain size, increased density, and higher crystallinity compared to the sonoCBD CdS films. The deposition rate for CdS obtained using pulsed DC magnetron sputtering was 2.86 nm/s using only 500 W power on a six inch circular target compared to the much slower (0.027 nm/s) for the sonoChemical bath deposited layers. CdTe thin films were grown on CdS films prepared by sonoCBD and Pulsed DC magnetron sputtering. The results showed that the deposition technique used for the CdS layer affected the growth and properties of the CdTe film and also determined the deposition rate of CdTe, being 3 times faster on the sputtered CdS. PDCMS CdTe layers were deposited at ambient temperature, 500 W, 2.9 μs, 10 s, 150 kHz, with a thickness of approximately 2 μm on CdS/TEC10 coated glass. The layers appear iii uniform and smooth with a grain size less than 100 nm, highly compact with the morphology dominated by columnar grain growth. Stress analysis was performed on the CdTe layers deposited at room temperature using different gas flows. Magnetron sputtered thin films deposited under low gas pressure are often subject to compressive stress due to the high mobility of the atoms during the deposition process. A possible way to reduce the stress in the film is the post-deposition annealing treatment. As the lattice parameter increased; the stress in the film is relieved. Also, a changing the deposition substrate temperature had an effect on the microstructure of CdTe thin films. Increasing the deposition temperature increased the grain size, up to ~600 nm. CdTe thin films with low stress have been deposited on CdS/TEC10 coated glass by setting the deposition substrate temperature at ~200°C and using high argon flows ~ 70 sccm Ar. Finally, broadband multilayer ARCs using alternate high and low refractive index dielectric thin films have been developed to improve the light transmission into solar cell devices by reducing the reflection of the glass in the extended wavelength range utilised by thin-film CdTe devices. A four-layer multilayer stack has been designed and tested, which operates across the wavelength range used by thin-film CdTe PV devices (400 850 nm). Optical modelling predicts that the MAR coating reduces the WAR (400-850 nm) from the glass surface from 4.22% down to 1.22%. The application of the MAR coating on a thin-film CdTe solar cell increased the efficiency from 10.55% to 10.93% or by 0.38% in absolute terms. This is a useful 3.6% relative increase in efficiency. The increased light transmission leads to improvement of the short-circuit current density produced by the cell by 0.65 mA/cm2. The MAR sputtering process developed in this work is capable of scaling to an industrial level.

Το οξείδιο του ψευδαργύρου (ZnO) ανήκει στην κατηγορία των διάφανων αγώγιμων οξειδίων και θεωρείται ως το ανόργανο υλικό που επιδεικνύει τη μεγαλύτερη ποικιλία χαμηλοδιάστατων νανοδομών. Νανοδομές διαφόρων μορφολογιών του ZnO αναπτύσσονται με πλήθος μεθόδων – με κυριότερες την αέρια μεταφορά σε υψηλή θερμοκρασία (VLS) και τη χημεία διαλυμάτων – και παρουσιάζουν μεγάλο εύρος πιθανών εφαρμογών σε τομείς όπως η οπτική, η οπτικοηλεκτρονική, οι αισθητήρες, η παραγωγή ενέργειας, οι βιοϊατρικές επιστήμες, κ.α. Παρά τη συστηματική έρευνα σχετικά με την ανάπτυξη των νανοδομών αυτών για πάνω από μια δεκαετία, η καθιέρωση μιας πειραματικής μεθοδολογίας ικανής να παρέχει με επαναλήψιμο τρόπο συγκεκριμένες μορφολογίες νανοδομών του ZnO είναι ακόμα ένα ανοικτό ερώτημα. Αυτό αποτελεί και μια από τις τρέχουσες ερευνητικές προκλήσεις αφού οι παραγόμενες μορφολογίες χαρακτηρίζονται από διαφορετικές φυσικές ιδιότητες ενώ είναι αρκετά ευαίσθητες σε μικρές μεταβολές των πειραματικών συνθηκών. Στόχος της παρούσας εργασίας είναι η συστηματική μελέτη του ρόλου διαφόρων παραμέτρων της σύνθεσης στα μορφολογικά χαρακτηριστικά και τις οπτικές ιδιότητες των νανοδομών του ZnO. Η ανάπτυξη των νανοδομών πραγματοποιήθηκε τόσο με αέρια μεταφορά σε υψηλή θερμοκρασία (VLS) όσο και με τη μέθοδο της κρυστάλλωσης σε υδατικά διαλύματα (CBD). Σκοπός είναι να κατανοηθεί πως συγκεκριμένες παράμετροι επηρεάζουν τη μορφολογία των νανοδομών, το μέγεθος, τις κατανομές των διαμέτρων των μονοδιάστατων νανονημάτων και τον προσανατολισμό αυτών στο υπόστρωμα. Στην πρώτη περίπτωση δόθηκε έμφαση στο ρόλο του πάχους του υμενίου του καταλύτη (Au), αλλά και στον τρόπο ανόπτησης αυτού ώστε να δημιουργηθεί η κατάλληλη μορφολογία του καταλύτη η οποία μέσω της ανάπτυξης με τη μέθοδο VLS επηρεάζει κατ’ επέκταση και τη μορφολογία των νανοδομών του ZnO. Έτσι, επιχρυσωμένα υποστρώματα πυριτίου (Si) με πάχος καταλύτη (h) από 2 nm έως 15 nm χρησιμοποιήθηκαν μετά από ανόπτησή τους σε διάφορες θερμοκρασίες και για διαφορετικούς χρόνους για την ανάπτυξη νανονημάτων ZnO. Διαπιστώθηκε ότι για πολύ λεπτά υμένια Au (h ≤ 3 nm) δημιουργούνται σφαιρικά νανοσωματίδια χρυσού και ο χρόνος ανόπτησης δεν επηρεάζει τη μορφολογία και την κατανομή μεγεθών. Για παχύτερα υμένια (h ≥ 5 nm), ανόπτηση για σύντομο χρόνο δεν επαρκεί για την ανάπτυξη νανοσωματιδίων αντίστοιχα με αυτά των λεπτών υμενίων. Στην περίπτωση αυτή, η αύξηση του χρόνου ανόπτησης ή/και αύξηση της θερμοκρασίας ανόπτησης είναι επιβεβλημένη για την ελάττωση του μέσου μεγέθους. Εν γένει, ανόπτηση σε χαμηλότερη θερμοκρασία (400 °C) για μεγάλο χρονικό διάστημα (30 λεπτά) μετατρέπει τα υμένια του Au σε νανοσωματίδια με ευρείες κατανομές μεγεθών και υψηλές μέσες τιμές. Η ανάπτυξη νανονημάτων ZnO εξαρτάται από το μέσο μέγεθος των νανοσωματιδίων του Au. Η ανάπτυξη παρεμποδίζεται στα μεγάλα μεγέθη νανοσωματιδίων Au αφού ο υπερκορεσμός τους με Zn και O είναι αργός. Ως εκ τούτου, για τα υμένια Au με πάχος μεγαλύτερο από ~10 nm η ανάπτυξη νανονημάτων του ZnO είναι εξαιρετικά περιορισμένη. Στη δεύτερη περίπτωση, εξετάστηκε διεξοδικά ένα πλήθος παραμέτρων όπως η συγκέντρωση των αντιδρώντων στο διάλυμα, η παρουσία οργανικών ενώσεων για τον έλεγχο της διαμέτρου, οι ιδιότητες του πρόδρομου υμενίου κρυστάλλωσης στο υπόστρωμα, ο χρόνος κρυστάλλωσης, κ.α. Γυάλινα αγώγιμα υποστρώματα (FTO) στα οποία είχε εναποτεθεί πρόδρομο υμένιο πυρηνοποίησης, χρησιμοποιήθηκαν σε αυτή την περίπτωση για την ανάπτυξη νανονημάτων. Καλά προσανατολισμένες δομές κάθετες στο υπόστρωμα με διάμετρο ~30 nm και μήκος μέχρι ~7 μm δημιουργήθηκαν με χρήση 0.04 Μ ZnAc, 0.02 M HMTA, 0.16 M PEI και 0.04 M NH4OH σε υδατικό διάλυμα στους 95 οC. H χρονική διάρκεια των πειραμάτων κυμάνθηκε στο διάστημα 1 – 24 h. Η τιμή του pH του διαλύματος ήταν περίπου 7. Ο προσανατολισμός των νανοδομών χειροτέρευε με αύξηση του μήκους τους καθώς κάμπτονταν και ενώνονταν με τα γειτονικά τους. Επομένως, για την βελτίωση της δομής τους βρέθηκε ότι είναι απαραίτητη η ανανέωση του διαλύματος κάθε ~2.30 h. Οι παραχθείσες νανοδομές εξετάστηκαν με ηλεκτρονική μικροσκοπία σάρωσης (SEM) και περίθλαση ακτίνων – Χ (XRD). Για την μελέτη των ατελειών στους κρυστάλλους του ZnO χρησιμοποιήθηκε η φασματοσκοπία Raman και η φασματοσκοπία φωτοφωταύγειας (Photoluminescence). Με την φασματοσκοπία Raman μελετήθηκαν οι τρόποι δόνησης των μορίων του υλικού, ενώ με τη φασματοσκοπία φωτοφωταύγειας η ύπαρξη ατελειών στον κρύσταλλο, όπως έλλειψη οξυγόνου, αντικατάσταση ψευδαργύρου με οξυγόνο, κλπ. / Zinc oxide (ZnO) is one of the most important low dimensional semiconducting oxides owing to the amazing variety of the nanostructures it can form by means of various synthesis routes. The most important methods are the vapor deposition and the chemical bath deposition. ZnO nanostructures have attracted considerable attention in view of several applications they encounter such as optics – optoelectronics, sensors, energy production, biomedical sciences, etc. Despite systematic research concerning the rational growth of ZnO nanostructures for over a decade, the establishment of an experimental methodology capable of providing specific morphologies of ZnO nanostructures in a reproducible way is still an open question. This is also one of the current research challenges because the resulting morphologies are characterized by different physical properties and are quite sensitive to small changes in experimental conditions. The current work is aimed at providing a systematic study of the role of various growth parameters on the morphological features and the optical properties of ZnO nanostructures. Growth was achieved by catalyst-assisted (Au) vapor transport at high temperature (VLS) and by solution chemistry (CBD). It is important to gain understanding about how certain parameters affect the morphology of the nanostructures, the size distributions of the diameters and their orientation relative to the substrate. High temperature evaporation methods, such as the vapor-liquid-solid mechanism, have been exploited for the controlled growth of ZnO nanostructures on various substrates. While Au is the most frequently used catalyst for growing ZnO nanowires, its morphological features on the substrate, which determine the size and shape of the nanostructures grown, are not yet methodically explored. In the current work, we investigated the details of thermal dewetting of Au films into nanoparticles on Si substrates. Au films of various thicknesses, h, ranging from 2 to 15 nm, were annealed under slow and fast rates at various temperatures and the morphological details of the nanoparticles formed were investigated. The vapor-liquid-solid method was employed to investigate the role of the Au nanoparticles on the growth details of ZnO nanowires. Efficient and high throughput growth of ZnO nanowires, for a given growth time, is realized in cases of thin Au films, i.e. when the thickness is lower than 10 nm. In the second case, the influence of a number of parameters such as the thickness of the seed layer, the reactants concentration, the existence of organic compounds, the growth time, etc. on the growth of ZnO nanowires on conducting glass substrates (FTO) was examined. After parameter optimization it was found that ZnO nanowires grown have excellent orientation, perpendicular to the substrate, while their diameter and length were found to be ~30 nm and ~7 μm, respectively. The best growth conditions were achieved using 0.04 Μ ZnAc, 0.02 M HMTA, 0.16 M PEI and 0.04 M NH4OH. The reaction temperature was kept at 95 οC for 1 h to 24 h. The pH value was ~ 7. The alignment of ZnO nanowires deteriorates when their length increases; therefore neighboring nanowires bend forming bundles. This shortcoming has been overcome by employing the renewal of the solution every 2.30 h. The structure of ZnO nanowires was investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Raman scattering was used to study defects of ZnO nanostructures. New Raman modes, in comparison to the bulk crystal, have been assigned to finite size effects and phonon confinement in the nanostructures. Photoluminescence spectroscopy provides evidence for the type of the defects such as oxygen vacancies, zinc interstitials etc.