Properties of intrinsic a-Si films deposited from higher order silanes by chemical vapor deposition

Amorphous silicon films have been deposited by chemical vapor deposition using disilane at temperatures between 360 and 5250C at growth rates up to 50 A/s. Intrinsic films have the following properties: σrho less than 5 x 10-6 (Ω-cm)-1; σd less than 5 x 10-11 (Ω-cm)-1 with Ea = 0.7 to 0.8 eV; diffusion length around 0.1 μm; Urbach energy 48 to 55 meV; and mid-gap density of states greater than 5 x 1016 cm-3 eV-1. Boron compensation improved collection efficiency by lowering the mid-gap density of states, not by improving the μtau product. Pin cells with efficiencies of 4% and Jsc = 10.9 mA/cm2 (87.5 mW ELH) were fabricated