Spectral photoconductivity and in-plane photovoltage studies of as-grown and annealed GaInNAs/GaAs and GaInAs/GaAs quantum well structures

Abstract

We present an investigation of thermal annealing effects on spectral photoconductivity and in-plane photovoltage, at temperatures between 30 K and 300 K, in sequentially grown GaInNAs/GaAs and GaInAs/GaAs quantum well structures. Our results indicate that thermal annealing not only improves the sample quality but also causes the blueshift as commonly observed by other groups in optical studies. We show that the observed anneal-induced blueshift behaviour can be explained in terms of two competing mechanisms: the redistribution of nearest neighbour configuration and the change of quantum well. profile. We also show that thermal annealing increases the intensity of photoconductivity signal but reduces the in-plane photovoltage signal drastically.