%0 Journal Article
%A Fischer, Benedikt
%A Beyer, Wolfhard
%A Lambertz, Andreas
%A Nuys, Maurice
%A Duan, Weiyuan
%A Ding, Kaining
%A Rau, Uwe
%T The Microstructure of Underdense Hydrogenated Amorphous Silicon and its Application to Silicon Heterojunction Solar Cells
%J Solar RRL
%V 7
%N 10
%@ 2367-198X
%C Weinheim
%I Wiley-VCH
%M FZJ-2023-01670
%P 2300103 -
%D 2023
%X The application of thin underdense hydrogenated amorphous silicon (a-Si:H) films for passivation of crystalline Si (c-Si) by avoiding epitaxy in silicon heterojunction (SHJ) solar cell technology has recently been proposed and successfully applied. Herein, the microstructure of such underdense a-Si:H films, as used in our silicon heterojunction solar cell baseline, is investigated mainly by Raman spectroscopy, effusion, and secondary ion mass spectrometry. In H effusion experiments, a low-temperature (near 400 °C) effusion peak which has been attributed to the diffusion of molecular H2 through a void network is seen. The dependence of the H effusion peaks on film thickness is similar as observed previously for void rich, low substrate-temperature a-Si:H material. Solar cells using underdense a-Si:H as i1-layer with a maximum efficiency of 24.1% are produced. The passivation quality of the solar cells saturates with increasing i1-layer thickness. The fact that with such underdense material combined with a following high-quality i2-layer, instead of only high-quality a-Si:H with a low defect density direct on the c-Si substrate, good passivation of c-Si solar cells is achieved, which demonstrates that in the passivation process, molecular hydrogen plays an important role.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000949562600001
%R 10.1002/solr.202300103
%U https://juser.fz-juelich.de/record/1006435