Analysis of electronic transport in HIT solar cells

摘要: Heterojunction with intrinsic thin-film (HIT) solar cells combine the strengths of amorphous and crystalline silicon to create very efficient stable devices. In fact, they have potential replace based on monocrystalline technology; current cell market leader. The production can be done cheaper, at lower temperatures a potentially higher open circuit voltage Voc. To advance technology, much research is in optimizing performance HIT For purposes it valuable completely understand physics A model that adequately describe behaviour device could used simulate different architectures, without going through process manufacturing, measuring characterization. This would significantly speed up optimization process. Unfortunately, no such exists thus lot find one. aid this, goal this thesis dominant electronic transport mechanisms cells, because despite several previous studies consensus has been reached. characterize currents are present device, number measurements were performed, most importantly which dark current-voltage (JV) measurement, where temperature was varied. From four regions distinguished: reverse bias region (V < 0) , low forward (0 V 0.4) high (0.4 0.7) limited (0.7 0.9). every JV each fitted fitting function. information from these fittings found optimized parameters choice function accurately current. activation energy saturation Eact exponential factor extracted. also possible calculate diode ideality n. These quantities unique for certain mechanism as identify transport. It concluded best described by multitunneling capture-emission model, an Eact;LFB = 0.3 - 0.45 eV logarithmic slope 3.5-4.5 V-1. still unclear. combination Eact-HFB 0.55 -0.75 n 1.25 1.4 does not correspond any known mechanism. However, alternative method calculates average ~1.8 1.9, lead conclusion dominated recombination bias, space-charge series resistance observed, probably due area measured samples. usually reported everse-bias generation current, but reasonable assume actual parallel, ohmic path reverse-bias characteristics tunneling dominates bias. Additionally, influence thickness doping level emitter layer investigated. possibly drift depositions inaccurate specifications, yielded many results. only trends observed decrease increases passivation Voc influences quite weak additional needs before anything concluded.