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A key to solar cells with lower environmental impact is higher efficiency and reduced material usages. Bifacial solar cells may have a higher efficiency as light can enter from two directions and tandem solar cells may use a larger part of the incoming solar spectrum, increasing the efficiency. However, both these applications require transparent and conducting contacts. This thesis aimed to investigate how suitable the transparent conductive oxides aluminum doped zinc oxide (AZO) and indium doped tin oxide (ITO) are as contacts in bifacial CIGS cells or CIGS/Silicon tandem cells. The contacts must remain stable when CIGS is deposited on top of it, meaning that they have to endure first 500°C and then 600°C in combination with copper, indium, gallium and selenium vapours. A thin layer of AZO topped with ITO and pure ITO films of different thicknesses were deposited by RF- and DC-sputtering, varying the oxygen flow. Opto-electrical characterization showed that the transparency in the infrared was balanced against high conductivity due to a shift in the plasmon peak's position. No great difference was seen between pure ITO samples and AZO/ITO samples, so only the first where further processed. The ITO films were annealed to 500°C in the CIGS deposition chamber, exposed to selenium vapour. The films' sheet resistances dropped drastically, which was mainly attributed to activation of tin donors. ITO produced with low oxygen flows also appeared more crystalline according to x-ray diffraction measurements. Photon absorption in the ITO was used to estimate the current loss in bifacial and tandem applications and graphs with current loss and sheet resistance can be used to select an ITO deposition process. Commercial ITO was exposed to 100s of the CIGS deposition process but only during selenium and gallium vapour. A layer of gallium selenide could be identified on the surface, but the ITO appeared to remain stable. Sodium fluoride pre deposition treatment lowered the samples absorption for all wavelengths compared to non-treated samples.

Since the surprising first detection of small carbon cluster dianions by Compton et al 1990, several studies have been made investigating their structure, fragmentation pathways and stability. As other carbon anions have been found in space, it is likely that these dianions exists as well and their ability to react with other molecules is therefore of interest. Previous studies have shown that they may survive on microsecond timescales, but it is still an open question whether they are metastable or thermodynamically stable. Therefore, this study utilizes the cyrogenic storage ring DESIREE to investigate the lifetime and stability of carbon cluster dianions Cn(2-) (n=7-10) in the new domains. Dianions were produced with a cesium ion sputtering source and their spontaneous decay Cn(2-) -> Cn(-) + e- was monitored for almost 100 ms by detection of the singly charged decay products. Also, the extra electron's tunneling probability through the repulsive coloumb barrier for C8(2-) was calculated and the lifetime for different energy states was estimated. Analyzing the DESIREE data, the lifetime of the dianions could be determined to exceed the previous concluded lifetimes of 10 us by a whole order of magnitude. The only way to detect stable ions after that would be if they collided with rest gas and due to good vacuum, this eventual signal is too low. Probably due to varying structures, an alternating pattern was found, dianions with even n decaying slower than their odd neighbours. The fitting of power laws to the data is consistent with that the dianions were produced with a broad internal energy distribution. Calculations for C8(2-) indicated that its electron affinity had to be at least -1eV in order to agree with the experimental results. Continuing the investigations, future studies could, after sufficient time, use DESIREE in an alternative way, allowing detection of possible stable dianions.