Selective area epitaxy of InGaAs/InGaAsP quantum wells studied by magnetotransport

Abstract

Selective area epitaxy can have a marked effect on the growth of quantum well structures by metal-organic vapour phase epitaxy. An understanding of the resulting modifications to the layer thicknesses and compositions is important for the fabrication of integrated devices. In this paper we present magnetotransport measurements from modulation-doped InGaAs/InGaAsP multi-quantum wells grown on InP substrates patterned with silica masks. The observed increase in carrier density with decreasing width of the conducting channel is related to changes induced by the selective area growth. A self-consistent solution of the Schrödinger and Poisson equations is used to calculate the modifications to the band profile. The occupation of two subbands in one of the structures allows the subband separation to be extracted from the magnetoresistance data, leading to an estimate of the well thickness over three times its nominal value.