Directly bonded Ge/GaAs by surface activated bonding for high efficiency III–V multi-junction solar cells

Abstract

Ge/GaAs wafers have been bonded by surface activated bonding. TEM observation of the bonded interface shows that amorphous layer with thickness of about 5 nm has been formed. I-V characteristic of directly bonded p-Ge/p-GaAs shows diode-like properties. The electrical resistance of the bonded interface has achieved about 0.16 Ωcm2 at 0.1 V.