GaAsBi MQWs for multi-junction photovoltaics

A GaAsBi/GaAs multiple quantum well diode with a p-i-n structure including a 0.6μm i-region containing a 40 periods of 8nm well and 7.4nm barriers has been grown by molecular beam epitaxy. The photocurrent of the fabricated device was measured and compared to that of a strain-balanced 65 period InGaAs/GaAsP MQW p-i-n diode grown by metal-organic vapour phase epitaxy. The GaAsBi device exhibits an ideality factor of 1.8 and a photoluminescence peak at 1055nm. The photocurrent of the GaAsBi device was comparable to that of the InGaAs/GaAsP device at around 920nm but continued to produce current out to ~1100nm.