Gallium Arsenide Solar Cells Grown on Polycrystalline Germanium Substrates by Aluminum-Induced Crystallization

In this study, gallium arsenide solar cells were grown on three substrates: a polycrystalline germanium substrate created by aluminum-induced crystallization, a polycrystalline germanium substrate with an average grain size of 400 μm from Umicore, and a monocrystalline (100) germanium substrate with a 6° offcut from Umicore. The solar cells created by aluminuminduced crystallization showed a V
_OC
up to 0.17 V, which was comparable to the solar cells grown on the Umicore polycrystalline germanium substrates that exhibited a range of V
_OC
from 0.20 V to 0.40 V. Device performance further improved when concentrating the solar cells, where a V
_OC
of 0.4 V, J
_SC
of 7.9 mA/cm
²
, and an efficiency of 0.023% was achieved under 67 suns for the solar cells grown on a germanium substrate prepared by aluminum-induced crystallization.