LOW-TEMPERATURE MAGNETOPHOTOLUMINESCENCE INVESTIGATIONS OF THE 2D HOLE SYSTEM IN P-TYPE GAAS-ALGAAS HETEROJUNCTIONS

Bandgap magneto-photoluminescence (PL) has been used to investigate th e optical signature of high quality p-type GaAs-Al(x)Ga1-xAs single he terojunction samples in the quantum Hall effect (QHE) regime. The PL s pectra show a series of sharp lines, with a number of bulk features at tributed to free exciton emission and acceptor-related bound excitons evident. Significantly, however, one line within the complex PL spectr um, at slightly lower energy to the free exciton, becomes a dominant f eature at low temperatures and has an intensity maximum which exhibits superlinear behaviour with excitation power that correlates with the nu = 1 QHE. This line is assigned to an excitonic process at the heter ointerface reminiscent of 2D excited subband recombination in n-type s tructures.