Fabrication of heterojunction solar cells by using microcrystalline hydrogenated silicon oxide film as an emitter

Abstract

Wide gap, highly conducting n-type hydrogenated microcrystalline silicon oxide (μc-SiO : H) films were prepared by very high frequency plasma enhanced chemical vapour deposition at a very low substrate temperature (170 °C) as an alternative to amorphous silicon (a-Si : H) for use as an emitter layer of heterojunction solar cells. The optoelectronic properties of n-μc-SiO : H films prepared for the emitter layer are dark conductivity = 0.51 S cm−1 at 20 nm thin film, activation energy = 23 meV and E04 = 2.3 eV. Czochralski-grown 380 µm thick p-type ⟨1 0 0⟩ oriented polished silicon wafers with a resistivity of 1–10 Ω cm were used for the fabrication of heterojunction solar cells. Photovoltaic parameters of the device were found to be Voc = 620 mV, Jsc = 32.1 mA cm−2, FF = 0.77, η = 15.32% (active area efficiency).