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The aim of this thesis is the characterization of electrical properties of solar cell using CCD camera. Diagnostic methods are based on electroluminescence and microplasma emitted from the surface of the solar cell. The results are then compared with the method LBIC (Light Beam Induced Current) and described the various defects in industrial production.

This thesis presents the development of innovative tools to investigate spatially distributed properties of thin film photovoltaic devices. They are required to gain a better understanding of device behaviour driven by how such properties affect the performance of commercial-scale devices. The tools developed for this are a distributed 3D model (D3DM) as simulation software and a laser beam induced current (LBIC) system as a platform for characterisation. The D3DM was developed utilising standard circuit analysis software. It is constructed to simulate realistic device structures and current flows in thin film PV devices. Diode parameters are truly distributed and can be varied independently. The model includes a voltage dependent photocurrent which is a key characteristic of amorphous silicon based solar cells. The D3DM has been used for the investigation of spatial variation in performance due to the distributed nature and non-uniformity of diode parameters and solar cell properties. It is shown that distributed series resistance contributed from the contact layers has a significant impact on solar cell performance and efficiency. The LBIC system is an optical scanning based characterisation tool. Unlike most existing systems, this has been developed specifically for large area, module-size thin film applications. The system provides a detailed photocurrent map which reveals spatial non-uniformity and allows investigation of localised performance variation of the investigated PV devices. System development, components and their characterisation as well as different measurement techniques are described. The model is also applied to LBIC measurements where it is used for a sensitivity analysis of measurement signal with respect to certain cell parameters in cells and modules under different measurement conditions. A new limiting illuminated LBIC (li-LBIC) measurement technique was developed. It is a measurement where the laser-probed cell is brought into limiting condition by means of shading. The signal thus generated is a linear response which was previously unobtainable by typical LBIC measurements. It is unaffected by non-uniform illumination allowing the real properties of investigated cells in a monolithic series connected module to be measured non-destructively.

The importance of further research in the field of solar cells is crucial for the transition to cleaner energy. The aim of this project is to design and manufacture a contact system that can measure busbarless solar cells with an LBIC-system. In this project mono-crystalline busbarless solar cells were utilized, busbarless solar cells only have small fingers that go vertically. When an incident photon hits the solar cell it can be absorbed by the bulk material, by the pn-junction an electrical field will set the electrons in motion so an electrical current can be harvested. LBIC, which stands for light beam induced current is a technique to spatially map the quantum efficiency of a solar cell, there is also an availability to make phasemeasurements. There are two different quantum efficiencies, External quantum efficiency (EQE) and Internal quantum efficiency (IQE). The phase measurement of the LBIC shows how much resistance exists between the point of current-generation and the contacts where the current is collected. A contact system with a comb-like figure of phosphor bronze was manufactured and mounted on to the LBIC-machine. Several measurements were executed on two solar cells. This new contact system can measure busbarless solar cells, with a good connection to almost all the fingers on the solar cell. The lack of contact with some fingers seemed to not affect the end result too much. It isn’t vital to have contact with all fingers to get a decent LBIC-mapping. / Vikten av ytterligare forskning inom området solceller är avgörande för omställningen till renare energi. Syftet med detta projekt är att designa och tillverka ett kontaktsystem som kan mäta solceller utan busbars med ett LBIC-system. I detta projekt användes monokristallina solceller utan busbars, solceller utan busbars har endast smala fingrar som går vertikalt. När en infallande foton träffar solcellen kan den absorberas av bulkmaterialet, vid pn-övergången kommer ett elektriskt fält att sätta elektronerna i rörelse så att en elektriskström kan samlas in. LBIC, som står för light beam induced current är en teknik för att rumsligt kartlägga kvantverkningsgraden för en solcell, det finns även en möjlighet att göra fasmätningar. Det finns två olika kvanteffektiviteter, Extern kvanteffektivitet (EQE) och Intern kvanteffektivitet (IQE). Fasmätningen av LBIC visar hur mycket motstånd som finns mellan punkten för strömgenerering och kontakterna där strömmen samlas. Ett kontaktsystem med en kamliknande figur gjord av fosforbrons tillverkades och monterades på LBIC-maskinen. Flera mätningar utfördes på två solceller. Detta nya kontaktsystemet kan mäta solceller utan busbars, med bra anslutning till nästan alla fingrar på solcellen. Bristen på kontakt med enskilda fingrar verkade inte påverka slutresultatet alltför mycket. Det är alltså då inte nödvändigt att ha kontakt med alla fingrar för att få en anständig LBIC-mätning.

Subject this diploma thesis is introduction to solar problems, with folow-up focus on solar elements and reflection about their defects. The next part is dedicated diagnostic method LBIC (Light Beam Induced Current) that help to detect defects of solar elements. The work is concerned with aplication this method in general view, from construction of workplace, throuhg hardware to software. The last part is focused on results processing and analysis.

This dissertation main point is to take up with fotovoltanic cells metering methods. Dissertation work dwells with the most common defects rising during the fotovoltanic cells manufacturing. Also, there is a diagnosis workshop proposal and realisation. Workshop uses the Light Beam Inducted Voltages (LBIV) method. By the help of this method, fotovoltanic cells structures are analised and compared to the Light Beam Inducted Current (LBIC).

Depuis les années 1970, la taille des composants n’a cessé de diminuer. La réalisation de jonctions ultra-minces et fortement dopées est devenue un point clef dans la réduction des dispositifs microélectroniques. Les techniques de production doivent évoluer afin de répondre aux spécifications drastiques, en termes de taille des zones dopées et de leurs propriétés électriques, des prochains noeuds technologiques. Dans ce travail de thèse nous avons étudié le procédé d’activation au laser de dopants implantés par immersion plasma. Le laser à excimère utilisé (ArF) est absorbé dans moins de 10 nmde silicium, ce qui va permettre un recuit local. De plus, la courte durée d’impulsion va assurer un faible budget thermique, limitant la diffusion des dopants. En associant cette technique à l’implantation ionique par immersion plasma, dont l’intérêt est de pouvoir travailler à de très basses tensions d’accélération (quelques dizaines d’eV), nous pouvons réaliser des jonctions avec un fort taux d’activation sans diffusion. Après avoir présenté les différentes techniques de dopage pouvant être utilisées, nous avons décrit les dispositifs expérimentaux de traitement et de caractérisation utilisés. Des simulations ont permis de comprendre le rôle des paramètres laser sur le profil de température du siliciumen surface. Après avoir choisi le laser le plus adapté parmi les lasers ArF, KrF et XeCl (respectivement: 193 nm - 15 ns, 248 nm - 35 ns, 308 nm - 50 ns), nous avons observé l’effet du nombre de tirs et de la mise en forme de faisceau afin d’optimiser le procédé. Pour terminer, des inhomogénéités dues aux bords de faisceau ont été mises en évidence et étudiées afin d’enlimiter l’effet. / Since the 1970’s, the components size has steadily declined. The realization of highly-dopedultra shallow junctions became a key point in the reduction of microelectronic devices. Them anufacturing processes must evolve to meet the stringent specifications of the next technologynodes, in particular in terms of dimension and electrical properties of the doped area.In this thesis we have studied the process of laser annealing of dopants implanted by plasmaimmersion. The ArF excimer laser we used is absorbed in less than 10 nm of silicon, whichallows a local heating. Moreover, the short pulse duration provides a low thermal budget whichreduces the dopant diffusion. By combining this technique with plasma immersion ion implantation, which is interesting because of the very low acceleration voltage (few tens of eV), we can produce highly activated junctions without diffusion. After a presentation of the different doping techniques that may be used, we describe the experimental treatment and the characterization tools that we used. We have used numerical simulations to understand the role of the laser parameters on the temperature profile of the silicon surface. After choosing the most suitable laser between ArF, KrF and XeCl (respectively :193 nm - 15 ns, 248 nm - 35 ns, 308 nm - 50 ns), we studied the influence of the number of shots and beam shaping to optimize the process. Finally, inhomogeneities caused by the beam edgeshave been studied and identified in order to improve the laser scan process.

Il a été montré récemment (Mazur et al, Harvard University) qu'un moyen simple d'améliorer le rendement des cellules solaires photovoltaïques actuelles pouvait être obtenu en irradiant la structure du silicium avec des impulsions laser femtoseconde en présence d'un gaz sulfuré (SF6). Cette irradiation entraîne la formation de micro-structures érigées (spikes) sur la surface. Celle ci devient ainsi fortement absorbante au rayonnement solaire (black silicon). Le travail effectué durant cette thèse a porté sur plusieurs points. Dans un premier temps une étude complète a été menée sur les différents paramètres expérimentaux permettant la création de ces micro-structures à la surface du silicium. Parallèlement, des séries d'expériences ont été menées pour permettre la compréhension des mécanismes physiques entraînant leur formation. Par la suite, les surfaces de silicium micro-structurées ont été caractérisées optiquement. Les résultats obtenus permettent d'avoir une absorption de 96 % du silicium dans les spectre UV et visible. Des cellules solaires complètes ont été réalisées afin d'en caractériser électriquement les performances. / It was shown recently (Mazur et al, Harvard University) a simple way to improve the performance of photovoltaic solar cells could be obtained by irradiating the surface of silicon with femtosecond laser pulses in a sulfide gas atmoshere (SF6). This irradiation causes the formation of micro-structures (spikes) on the surface becomes highly absorbent to solar radiation (black silicon). The work done during this thesis focused on several points. Initially a comprehensive study has been conducted on different experimental setting allowing the creation of these micro-structure on the surface of silicon. Parallel series of experiments were conducted to help understand the physical mechanism leading to their formation. Subsequently, the surfaces of silicon micro-structured were characterized optically. The results obtained allow to have an absorption of 96% silicon in the UV and visible. Complete solar cells were made in order to electrically characterized perform.

The goal of this thesis is to, on behalf of JB Eco Tech, investigate a novel method of interconnecting photovoltaic (PV) modules. The principle is to stick the interconnecting strings on the cells with a transparent tape instead of soldering. As a part of the assembly process, the module is laminated under heat which makes the strings stick to the PV cell. The method is going to reduce one step in the production process, replacing the soldering procedure with the lamination of the strings onto the cells. Also, the replacement of lead and silver will spare costs and the environment. To analyse the effects of the novel method on the performance of the cell, the optical properties of the module were investigated by mathematical models and Light Beam Induced Current (LBIC). Also, the electrical properties were compared to the conventional method of soldering by analysing the I-V characteristics. The experiments were done on mini modules. Although the mini module displayed a reflectance of about 5.7 – 6.0% the contribution of the tape only accounted for a maximum of 0.5%. Since the tape only covers a fraction of the cell, this reflectance is negligible. Only 3 modules were successfully analysed, and the electrical properties of the novel method did not differ from the conventional method. To solidify the later a claim a more extensive rapport has to be made. The thesis opens up a new research area where improvements to the novel method can be done. / Det här examensarbetet är gjort på uppdrag av JB Eco Tech. De har utvecklat en ny metod i produktionen av solcells moduler. Syftet med studien är att undersöka metoden som baseras på att fästa transparant tejp med en belagd koppartråd på solcellerna istället för den konventionella metoden som använder sig av lödning. Metoden kommer att reducera ett steg i produktionskedjan genom att utesluta lödningsprocessen. Processen kommer också bidra till en minskning i användandet av silver och bly vilket bidrar till en reducerad kostnad och en minskad miljöpåverkan. För att analysera effekterna av prestandan till följd av den nya metoden så analyserades de optiska egenskaperna med hjälp av matematiska modeller och Light Beam Induced Current (LBIC). De elektriska egenskaperna hos solcells modulerna jämfördes med den konventionella metoden som involverar lödning genom att analysera I-V karakteristiken för de båda metoderna. De ovannämnda experimenten utfördes på miniatyr moduler. Resultaten som erhållits visade på att modulerna hade en reflektans av 5.7 – 6.0% och att tejpen endast stod för max 0.5%. Tejpen täcker endast en bråkdel av cellen därför går det att konstatera att reflektansen som härstammar från tejpen är försumbar. Det innebar att de optiska egenskaperna inte bidrog till en signifikant påverkan på prestandan av modulerna. De elektriska egenskaperna av modulerna påvisade ingen signifikant skillnad mellan de två olika metoderna. För att säkerställa det senare antagandet krävs en utökad studie inom området. Studien har öppnat upp för nya rön som grundas på den nya metoden där det finns utrymme för förbättringar av tejpen.

Les cellules solaires organiques continuent leur essor dans le domaine du photovoltaïque, grâce aux structures et matériaux activement étudiés, pour tendre vers le maximum de rendement et passer le cap de l'industrialisation. La séparation de phase des matériaux qui constituent la couche photo-active des cellules à hétérojonction en volume gouverne en partie les performances de la cellule, ainsi que des phénomènes de recombinaison liés à la photo-conversion. Des moyens de caractérisation spécifiques sont nécessaires pour sonder les propriétés des cellules aussi bien à l'échelle microscopique qu'à l'échelle nanométrique. Des bancs de caractérisations opto-électriques pour les cellules solaires organiques ont alors été développés. Ainsi, la technique du courant induit par faisceau lumineux (LBIC) permet de visualiser l'uniformité des cellules avec une résolution de 50µm. La microscopie à force atomique en mode conduction (C-AFM) permet quant à elle de sonder les propriétés photo-électriques des cellules à l'échelle du nanomètre. / Organic solar cells are becoming more prominent in the photovoltaic field thanks to new materials and stacked structures. The active layer of bulk heterojunction solar cells is composed of an interpenetrating network of electron donor and acceptor materials. Vertical phase separation governs cells power conversion efficiency and recombination phenomena are still being studied. Specific characterization tools are necessary to gain insights into cell properties at the nanometer scale and at the molecular level. In this context, this thesis allowed the development of electrical characterization tools for bulk heterojunction organic solar cells based on polymer/fullerene blend. Thus, the Light Beam induced Current (LBIC) technique has been developed to check the current uniformity of the cells with a 50µm resolution. Conductive-AFM (C-AFM) has been used to probe the photovoltaic properties of the cells in the nanometer range.