Electrical and Optical Properties of Amorphous and Microcrystalline Hydrogenated Silicon Films Deposited Using Saddle Field Glow Discharge

摘要

Amorphous (a-Si:H) and microcrystalline (μc-Si:H) hydrogenated silicon films were obtained using DC saddle field glow discharge. The structure of the films was determined by Raman spectroscopy, SEM and TEM. The optoelectronic characteristics of both a-Si:H and μc-Si:H were investigated using FTIR, UV/VIS spectroscopy, dark electrical conductivity (σ_d) and photoconductivity (σ_(ph)) measurements. Boron and phosphorous doping of a-Si:H and μc-Si:H films was also investigated. The results show that both a-Si:H and μc-Si:H undoped films are highly resistive (σ_d=10~(-8)-10~(-10) Ω~(-1)cm~(-1)). The doping efficiency of μc-Si:H films is much higher than a-Si:H films. The Tauc gap for a-Si:H was in the range 1.8-1.9 eV and for μc-Si:H films it was in the range 1.9-2.5 eV. The photoconductivity measurements of undoped films indicate a higher photosensitivity of a-Si:H films (σ_(ph)/σ_d=10~4) than that of μc-Si:H films (σ_(ph)/σ_d=10-100).