High quality passivation for heterojunction solar cells by hydrogenated amorphous silicon suboxide films

Abstract

In this letter, we report on our investigations of hydrogenated amorphous silicon suboxides (a-Si Ox:H) used as a high quality passivation scheme for heterojunction solar cells. The a-Si Ox:H films were deposited using high frequency (70 MHz) plasma enhanced chemical vapor deposition by decomposition of carbon dioxide, hydrogen, and silane at a substrate temperature of around 155 °C. High effective lifetimes of outstanding 4 ms on 1 cm n -type float-zone material and a surface recombination velocity of ≤2.6 cms have been repeatedly obtained. Optical analysis revealed a distinct decrease of blue light absorption in the a-Si Ox:H films compared to commonly used intrinsic amorphous silicon passivation used in heterojunction cells. © 2008 American Institute of Physics.