Impact of Sb Incorporation on MOVPE-Grown “Bulk” InGaAs(Sb)N Films for Solar Cell Application

Abstract

We have investigated the impacts of Sb incorporation on the microstructural, optical, electrical, and carrier dynamics properties of bulk InGaAsSbN films in a comparative study of InGaAsN and InGaAsSbN materials grown by metal-organic vapor phase epitaxy (MOVPE). These films were grown at the relatively high temperature of 600 °C and annealed at 800 °C for 30 min. Transmission electron microscopy studies indicate compositional and structural homogeneity of the InGaAsN and InGaAsSbN films. Low-temperature time-resolved photoluminescence measurements of the MOVPE-grown InGaAsN film show a longer minority carrier lifetime (~40 ns) than observed for the InGaAsSbN film (~26 - 27 ns). In addition, single-junction solar cells with an InGaAsN (InGaAsSbN) base layer exhibit an open-circuit voltage of 0.64 (0.58) V, a short-circuit current of 17.13 (16.89) mA/cm2 , a fill factor (FF) of 77.55 (74.29)%, and an efficiency of 8.57 (7.31)%. Sb incorporation in InGaAsN adversely affects solar cell performance due to a reduced minority carrier lifetime correlated with the formation of defects and narrow depletion region width resulting from a higher background carbon impurity level.