In this thesis, the structural, optical, and electrical properties of wurtzite MgxZn1-xO:Al and MgxZn1-xO:Ga thin films have been investigated in dependence on Mg and dopant concentration. Among the transparent conductive oxides (TCOs), ZnO based compounds have gained renewed interest as a transparent electrode for large scale applications such as defroster windows, at panel displays, touch screens, and thin film solar cells due to low material and processing cost, non-toxicity, and suitable physical properties. In general, these applications require transparent electrodes with lowest possible resistivity of rho < 10^-3 Ohmcm and lower [1]. Recently, it has been reported that Ga and Al doped ZnO thin films can be deposited with respective resistivity of 5x10^-5 Ohmcm [2] and 3 x10^-5 Ohmcm [3] which are similar to the data obtained for other practical TCOs, i.e. the resistivity of about 4x 10^-5 Ohmcm for Sn doped In2O3 (ITO) thin films [4]. Moreover, the bandgap of ZnO can be increased by alloying with Mg offering band alignment between transparent electrode and active (or buffer) layer of the device, e.g. Cu(In,Ga)Se2 solar cells [5]. The tunable bandgap of these transparent electrodes can further increase the efficiency of the devices by avoiding energy losses in the interface region of the layers. From this point of view, this work has been aimed to investigate the doping efficiency and limits in transparent conductive (Mg,Zn)O alloys. For this purpose, the samples investigated in this work have been grown by pulsed-laser deposition (PLD) using a novel, continuous composition spread method (CCS). In general, this method allows to grow thin films with lateral composition gradient(s) [6, 7]. All MgxZn1-xO:Al and MgxZn1-xO:Ga thin films have been deposited on 2-inch in diameter glass, c- or r-plane sapphire substrates using threefold segmented PLD targets in order to grow thin films with two perpendicular, lateral composition gradients, i.e. the Mg composition is varied in one direction whereas the Al/Ga concentration is varied in a perpendicular direction [7, 8]. In order to investigate the influence of the temperature, samples grown at different substrate temperatures in the range of 25 to 600 C were investigated. The optical and electrical measurements have been carried out on (5x 5)mm^2 samples that were cut from the CCS wafers along the respective composition gradients, i.e. Mg and Al/Ga contents. Subsequently, physical properties of thin films have been analyzed for a large range of Al/Ga content between 0.5 and 7 at.%, which corresponds to doping concentrations between 2x 10^20 and 3x 10^21 cm^-3, for different Mg contents x(Mg) ranging from 0.01 to 0.1. It has been found that practically the limiting the dopant concentrations is about 2 x10^21 cm^-3. Further, the electrical data suggests, that the compensating intrinsic defect is doubly chargeable hinting to the zinc vacancy (V_Zn) as microscopic origin. Increasing the dopant concentration above 2 x10^21 cm^-3 leads to a degradation of electrical and structural properties [8]. Further, the influence of growth and annealing temperatures on structural, electrical and optical properties of the films has been studied. For that purpose, Al and Ga doped (2.5 at.% = 1x10^21 cm^-3) Mg0.05Zn0.95O thin films have been chosen from CCS samples grown at T_g = (25 - 600) C . For both doping series, the samples grown at higher temperatures exhibit better crystalline quality compared to the samples grown at lower growth temperatures. As a result, samples grown at higher temperatures reveal higher Hall mobility. For the Al-doping series, the highest free charge carrier density of n = 8.2x 10^20 cm^-3 was obtained for an Mg0.05Zn0.95O:Al thin film grown at 200 C, with corresponding Hall mobility of mu = 13.3 cm^2/Vs, a resistivity of rho = 5.7x10^-4 Ohmcm, and optical bandgap of E_g = 3.8 eV. Interestingly, the free charge carrier density of n = (5 - 8) x 10^20 cm^-3 for samples grown with T_g > 300 C is clearly higher than the value of n = 1.25 x 10^20 cm^-3 that was obtained for the high temperature grown sample, i.e. at T_g = 600 C. Furthermore, for all T_g, Al-doped films have a higher doping efficiency than the Ga-doped counterparts. In order to look deeper into the microscopic origin of this behavior, the samples were post-annealed in vacuum at 400 C. Experimental results showed that the free charge carrier density of Al-doped samples first decreased and saturated afterward with increasing annealing time. On the other hand, the free charge carrier density of the Ga-doped samples first slightly increased and saturated with increasing annealing time. For both doping series, the saturation value of n ~ 1 x 10^20 cm^-3 was very close to the data that has been observed for (i) high temperature grown samples and (ii) the solubility limit of Al in ZnO of 0.3 at.% = 1.2x 10^20 cm^-3, that has been determined by Shirouzu et al. for high temperature grown (T_g > 600 C) Al-doped ZnO [9]. Correspondingly, the optical bandgap also changed, i.e. increased (decreased) for Al- (Ga-) doping series, and approached a constant value of 3.5 0 +- 0.1 eV which is explained by generation of acceptor-like compensating defects, and the solubility limit of the dopants. From XRD data, no secondary phases were found for as-grown and post-annealed films. However, the slight improvement of crystalline quality has been observed on post-annealed samples. Further, it has been shown that the growth and annealing temperatures are important as they strongly affect the metastable state of the solid solution that samples grown at low temperature represent. The low solubility limit of the dopants, i.e. 0.3 at.% for Al in ZnO under equilibrium condition, can be increased by preparing samples by non-equilibrium growth techniques [10]. This is also consistent with experimental results of this work that Al- as well as Ga-doped metastable ZnO and (Mg,Zn)O thin films can be prepared with highest possible doping efficiency for the dopant concentration up to 2.5 at.% when growth or annealing temperatures below 400 C are used.

This paper discusses the current and future drivetrain perspectives of powerful mobile machines, especially in regards to TCO and drive performance. For the TCO-impact, the power losses of the components plays a big role and, if they are designed for efficiency, they have a significant and measurable influence. From the braking function point of view, this paper demonstrates not only the advantages of a valve-based over a control algorithm based solution, but also its innovative development directions towards a more sophisticated engine speed controller with optimized heat conversion into the oil. Also for the drivetrain subsystems, innovative components are discussed, like the hybrid control, combining the benefits of a non-feedback and a displacement control in one single assembly, or the variable charge system for further reduced energy consumption of the overall drivetrain.

Solid state lighting is a new environmentally friendly light source. So far, light emitting diodes (LEDs) and organic LEDs (OLEDs) have been presented as candidates with potentially high efficiency. Recent advances of OLEDs in device architecture, light-out coupling, and materials have ensured high efficiency, exceeding that of incandescent light bulbs. In contrast to conventional point source LEDs, OLEDs distribute light throughout the surface area and are not restricted by their size. Additionally, OLEDs are expected to reach sufficient stability in the near future. The remaining challenge for OLEDs is their cost. New OLED technologies provide cost effective manufacturing methods which could be presented for transparent electrode materials because indium tin oxide (ITO), a widely used material as a transparent electrode for OLEDs, is less than optimal due to its high element price. In this work, alternative transparent electrodes for OLEDs as a replacement of ITO were studied. First, Al doped ZnO (ZnO:Al) which is composed of abundant materials was investigated with DC magnetron sputtering under a wide range of experimental conditions. The optimised ZnO:Al received comparable performance with conventional ITO films, low sheet resistance of 22.8 Ω/sq as well as a high transparency of 93.1 % (average value in the visible range). Various type of p-i-n OLEDs were employed on the structured ZnO:Al using photolithography. Green OLEDs with double emission layers have been archived stable efficiencies even at higher luminance. Also, OLEDs using two fluorescent colour system on ZnO:Al anode showed a purely white emission. It has been found that the OLEDs on ZnO:Al anode has comparable or better device efficiencies and operational lifetime compared to OLEDs on conventional ITO anode. As another alternative electrode, the conductive polymer Baytron®PH510 (PEDOT:PSS) was investigated. Due to a relatively high sheet resistance of PEDOT:PSS, metal grid was designed for large size OLEDs. White OLEDs on PEDOT anode with a size of 5 × 5 cm2 have achieved more than 10 lm/W of power efficiency using a scattering foil. Furthermore, up-scaled devices on 10 × 10 cm2 were also demonstrated. These results showed ZnO:Al and PEDOT are suitable for OLEDs as anode and have high potential as alternative transparent electrode materials.

Purpose. In Sweden, private commuting accounts for two third of total transportation emissions and 21% of the country’s total. To become net-zero by 2045, Sweden plans to have 2 million electric cars on the roads by 2030. Whereas with current pace, there will be 1 million electric cars by the end of the decade. Cars registered before 2016 (referred to as old cars in the study) make up nearly half of the Swedish car fleet. Thus, replacing the old emission intensive cars with the modern lower or zero emission cars will catalyze the decarbonization of Swedish transport sector. Therefore, the purpose of this study is to probe if it is economical to keep using an old car in the future or to replace it with a new one. Methods. This study first compares the next 13-year Total Cost of Ownership (TCO) of old V70 (having current milage 200,000 km) with that of new replacement cars. The (selected) replacement are the most registered modern-day cars in Sweden by fuel type having same size as that of V70: V60 (ICE), V60 (PHEV) and Tesla Model 3 (BEV). Moreover, using TCO framework, the study also estimates if the replacement is more economical now or sometime in the future with either new replacement cars or their (4-year) used models. Results. The results show that for next 13-years in Sweden, it is more economical to replace the old V70 with any of the replacement cars. However, Tesla Model 3 is the cheapest option among the new cars and V60 (PHEV) among the used cars. Overall, it is more economical to replace with a used car. In addition, the replacement is most economical if done immediately (in 2022) and gets more expensive by each year of delay- because the owner will have to incur relatively higher V70 costs (vis-à-vis the replacement cars) for an additional year. Sensitivity analysis shows that with higher current salvage value, a V70 gets more expensive to own in next 13 years (due to higher depreciation) whereas the replacement becomes cheaper (utilizing higher salvage value to buy the replacement car). Discussion. The study can be expanded to suggest economical and emission efficient replacement options for other old cars to accelerate the decarbonization of Swedish private transport sector. Furthermore, this study was done in collaboration with Mekonomen Group to see the financial worth of old ICE car replacement by its customers. The study results reinforce the group’s diversification strategy from ICE cars-oriented business model to BEVs as the top focus. Finally, this study is based on the assumption that the total number of cars in Sweden will not increase in future- the old gets replaced by the new. Therefore, from a holistic perspective, the study discusses that a sustainable transportation model should move away from private ownership towards shared mobility to avoid the rebound effects of technological efficiency that increase the overall resource consumption.

No description available.

The major barriers to a more widespread introduction of battery electric vehicles (BEVs) beyond early adopters are the limited range, charging limitations, and costly batteries. An important question is therefore where these effects can be most effectively mitigated. An optimization model is developed to estimate the potential for BEVs to replace one of the conventional cars in two-car households and to viably contribute to the households’ driving demand. It uses data from 1 to 3 months of simultaneous GPS logging of the movement patterns for both cars in 64 commuting Swedish two-car households in the Gothenburg region. The results show that, for home charging only, a flexible vehicle use strategy can considerably increase BEV driving and nearly eliminate the unfulfilled driving in the household due to the range and charging limitations with a small battery. The present value of this flexibility is estimated to be on average $6000–$7000 but varies considerably between households. With possible near-future prices for BEVs based on mass production cost estimates, this flexibility makes the total cost of ownership (TCO) for a BEV advantageous in almost all the investigated households compared to a conventional vehicle or a hybrid electric vehicle. Because of the ubiquity of multi-car households in developed economies, these families could be ideal candidates for the initial efforts to enhance BEV adoptions beyond the early adopters. The results of this research can inform the design and marketing of cheaper BEVs with small but enough range and contribute to increased knowledge and awareness of the suitability of BEVs in such households.

No description available.

The increasing energy demand, combined with the use of harmful non-renewable energy sources calls for the search of alternative methods to cover our energy need.Renewable energy can be harvested in different ways, through the movement of wind and water, biomass, or directly from the rays of the sun, as in the case of photovoltaic (PV) devices. Whilst crystalline silicon (c-Si) is the most common absorber used for solar cells, other technologies are emerging. Solar cells with copper indium gallium diselenide (CIGS) as an absorber have the possibility of being flexible, which is an advantage due to the many more application possibilities that appear compared to the rigid and heavy c-Si solar cells. CIGS solar cells have some long-term stability issues, especially regarding ingression of atmospheric species through the front contact layer. This calls for further research in the front contact of the CIGS solar cell, exploring alternative materials to prevent degradation. The front contact of a solar cell must be both optically transparent and conduct electricity. Transparent conductive oxides (TCO) are materials characterized by the ability to conduct electricity, while also possessing a certain degree of optical transparency. The combination of conductivity and transparency makes TCOs ideal as front contacts in solar cells. A very common TCO for front contacts in CIGS solar cells is aluminum-doped zinc oxide (AZO) due to its low cost, good electrical conductivity and optical transparency. Because of its low resistance to degradation in humid environments more robust TCO alternatives, such as indium-doped tin oxide (ITO), are being investigated. Indium-doped tin oxide possesses similar electrical and optical properties as AZO, but better stability in humid environments.The ITO was deposited through RF magnetron sputtering, on a glass substrate to be able to measure optical properties. Initially, experiments focusing on oxygen content in the deposition atmosphere were done, together with a reproducibility experiment. This gave useful information about sputtering parameters and stability of the deposition. Thereon, an experiment was done varying three parameters: oxygen content in deposition atmosphere, sputtering power and temperature of substrate. A statistical software was used to analyze the data, identifying the effects of the changing parameters. The best performing samples were made with an oxygen content of 0,4-0,6 vol%. A high sensibility for oxygen in the system was also observed, as a result of the initial reproducibility experiments. This led to the introduction of a sacrificial deposition step after the machine had been shut down. Optimal substrate temperature was around 150°Cand it was not possible to go higher due to sensibility of the underlying solar cell layers.A lower threshold for the film thickness, located somewhere between 125 and 175 nm, was observed. Films with thickness below this threshold experienced a large resistivityincrease. Further depositions with higher oxygen content are advised to see if the properties of the films further improve.

Functional and cost effective systems for the full electrification of a bus network are areas of intense research and development. The electrification can be accomplished using different technological solutions, for example using opportunity charging or using an electric road system – ERS. Both opportunity charging and ERS have the potential to be integrated into already existing bus lines. With opportunity charging, the regular dwell time at the end stops is used for the bus to recharge its batteries and with an ERS the bus can charge dynamically along the road. The purpose of this report is to analyze how the existing Alfa- and Beta line at Stockholm Arlanda Airport, in a functional and cost effective way, can be electrified using either opportunity charging or an ERS. The tradeoff between required charging power, battery capacity and the necessity to change the existing running schedule is explained in detail. In addition, the impact on the electrical grid is analyzed based on different load profiles of different charging stations using different power levels. The analysis is based on real data from the Alfa – and Beta line with its existing buses, the electrical grid at Arlanda and data provided by both the leading (electrical) bus manufacturers and the leading charging infrastructure manufacturers.  The outcome of this report suggests that a full electrification of the existing Alfa- and Beta line has the potential to lower CO2-emissions and energy use at a functional and cost effective way.

The essays main intent is to examine whether there has been a proper implementation of the Council’s directive 1999/70/EG into Swedish law regarding the requirement for measures to prevent the abuse of successive fixed-term employment contracts. To achieve this purpose there is a need for an examination of current law. The essay also has some secondary purposes. One of these secondary purposes is the question of whether the implementation of the Council’s directive 1999/70/EG has lead to a reduction of the workers employment protection, which is closely connected to my main question and the violation case. My other secondary purposes are to make a connection between fixed-term employment and labor market flexibilization and flexicurity, to see if the rules about fixed-term work has affected gender equality, and to discuss whether there has been a shift of power in the relationship between employers and employees. I have come to the conclusion that Sweden has not implemented the Council’s directive 1999/70/EG properly regarding the requirement for measures to prevent abuse of successive fixed-term employments. I have found that the Swedish rules that apply today may be circumvented by combining various forms of fixed-term employments and that some forms of fixed-term employment requires a more clear definition. To prevent the abuse of successive fixed-term contracts, I suggest the introduction of a maximum total duration for all forms of fixed-term employment together, combined with a rule about the maximum number of times a fixed-term employment contract may be renewed. Furthermore I have found factors indicating that a reduction of workers employment protection level has taken place, but I can not draw any firm conclusions about it because the essay has not examined the issue in a completely thorough manner. I have also found a connection between labor market flexibilization and the use of fixed-term employment and that Sweden should examine whether the flexicurity-model can provide some useful solutions to increase employment without reducing workers employment protection level. Gender equality regarding the share of fixed-term employment contracts has slightly increased, both in Sweden and in the EU, since the origin of the Council’s directive 1999/70/EG. Also I have found that the new rules for fixed-term employment may have resulted in a shift of power that favors the employer. / Uppsatsen syftar främst till att undersöka huruvida det skett en korrekt implementering av visstidsdirektivet i svensk rätt avseende kravet på åtgärder för att förhindra missbruk av flera på varandra följande visstidsanställningar. För att uppnå detta syfte krävs en utredning av gällande rätt. Uppsatsen har också några underordnade syften. Ett av dessa underordnade syften är frågan om huruvida implementeringen av visstidsdirektivet inneburit en minskning av arbetstagarnas anställningsskydd, som är nära kopplat till min huvudsakliga fråga och överträdelseärendet. Mina andra underordnade syften är att koppla reglerna om tidsbegränsade anställningar till arbetsmarknadens flexibilisering och flexicurity, att se om reglerna om tidsbegränsade anställningar påverkat jämställdhet mellan könen och att diskutera huruvida det skett förändringar i maktförhållandet mellan arbetsgivare och arbetstagare. Jag har kommit fram till slutsatsen att Sverige inte har implementerat visstidsdirektivet på ett korrekt sätt avseende kravet på åtgärder för att förhindra missbruk av flera på varandra följande visstidsanställningar. Jag har konstaterat att de svenska reglerna som gäller idag kan kringgås genom att olika former av tidsbegränsade anställningar kombineras och att vissa av anställningsformerna kräver en tydligare definition. För att förhindra missbruk av flera på varandra följande visstidsanställningar föreslår jag att det införs en övre sammanlagd tidsgräns för alla tidsbegränsade anställningsformer kombinerat med en regel om maximalt antal gånger ett tidsbegränsat anställningsavtal får förnyas. Jag har funnit faktorer som visar på att en minskning av arbetstagarskyddet har skett, men jag kan inte dra några säkra slutsatser om det eftersom uppsatsen inte behandlat frågan på ett uttömmande sätt. Vidare har jag funnit ett samband mellan arbetsmarknadens flexibilisering och användandet av tidsbegränsade anställningar och att Sverige borde undersöka om flexicurity-modellen kan bidra med några lösningar för att öka sysselsättningen utan att minska nivån på arbetstagarnas anställningsskydd. Jämställdhet mellan könen rörande andelen tidsbegränsat anställda har ökat något, både i Sverige och EU, sedan visstidsdirektivets tillkomst. Jag har också kommit fram till att de nya reglerna om tidsbegränsade anställningar kan ha inneburit en maktförskjutning som gynnar arbetsgivaren.