The Optical And Electrical Properties Of A-Si:H(nc-Si:H)/a-SiC:H Multilayer Films

The a-Si:H/a-Si C:H multilayer film was prepared on the quartz substrates and crystalline silicon by radio frequency plasma enhanced chemical vapor deposition technique(RF-PECVD), with H2 diluted CH4 and Si H4 as reaction gas sources. The nc-Si:H/a-Si C:H multilayer films with controlled crystallite size are formed by annealing at high temperatures.The samples’ microstructures are characterized and represented by transmission electron microscope(TEM), X-ray diffractometer(XRD), as well as Raman spectroscopy. It indicate that the multilayer structure film have good steep interfaces and periodic structure; The nanocrystalline silicon will grow to considerable size as the thickness of the well under the annealing temperature of 1050℃. The transmission and reflection of nc-Si:H/a-Si C:H multilayer structure film are measured by spectrophotometryphotometer, the result show that:the optical absorption coefficient decrease and optical band gap increase with the decreasing of well layer thickness; the barrier layer thickness has little effect on the optical absorption of the film.Longitudinal transport properties of a-Si:H(nc-Si:H)/a-Si C:H multilayer film is measured by semiconductor characterization analyzer, analyses show that sequential resonant tunneling peculiarities on the vertical direction of a-Si:H/a-Si C:H multilayer were observed,for nc-Si:H/a-Si C:H multilayer, tunneling mechanism at high electric field is Direct Tunneling,but carriers’ transport correspond to Fowler–Nordheim(FN) tunneling mechanism at high electric field.