Carrier Transport Through Grain Boundaries in Hydrogenated Microcrystalline Silicon

Abstract

ABSTRACTTo analyse the influence of the grain boundaries (gb) on the transport of carriers in hydrogenated microcrystalline silicon (μC-Si:H) the ambipolar diffusion length (LLMB) was measured by SSPG. In addition, the films were characterised by photo-conductivity, dark conductivity activation energy, Urbach energy (determined by CPM), hydrogen effusion, Raman spectroscopy, X-ray scattering and optical transmission.The sample series was prepared by PECVD of SiH4 diluted with increasing H2 content. Taking the structural information by Raman spectra and X-ray into account, we explain our optical and activation energy measurements within a three-phase-model (amorphous phase, crystalline phase, gb) and a Fermi level pinning in μc-Si:H.