Optical and Electrical Effects of p-type μc-SiO x:H in Thin-Film Silicon Solar Cells on Various Front Textures

Abstract EN

p-type hydrogenated microcrystalline silicon oxide (µc-Si O x :H) was developed and implemented as a contact layer in hydrogenated amorphous silicon (a-Si:H) single junction solar cells.

Higher transparency, sufficient electrical conductivity, low ohmic contact to sputtered ZnO:Al, and tunable refractive index make p-type µc-Si O x :H a promising alternative to the commonly used p-type hydrogenated microcrystalline silicon (µc-Si:H) contact layers.

In this work, p-type µc-Si O x :H layers were fabricated with a conductivity of up to 10−2 S/cm and a Raman crystallinity of above 60%.

Furthermore, we present p-type µc-Si O x :H films with a broad range of optical properties (2.1 eV < band gap E 04 < 2.8 eV and 1.6 < refractive index n < 2.6 ).

These properties can be tuned by adapting deposition parameters, for example, the CO2/SiH4 deposition gas ratio.

A conversion efficiency improvement of a-Si:H solar cells is achieved by applying p-type µc-Si O x :H contact layer compared to the standard p-type µc-Si:H contact layer.

As another aspect, the influence of the front side texture on a-Si:H p-i-n solar cells with different p-type contact layers, µc-Si:H and µc-Si O x :H, is investigated.

Furthermore, we discuss the correlation between the decrease of V oc and the cell surface area derived from AFM measurements.