Ag. Davies et al., LOW-TEMPERATURE MAGNETOPHOTOLUMINESCENCE INVESTIGATIONS OF THE 2D HOLE SYSTEM IN P-TYPE GAAS-ALGAAS HETEROJUNCTIONS, Physica. B, Condensed matter, 201, 1994, pp. 397-402
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.