Low-temperature photoluminescence of epitaxial InAs

Photoluminescence studies as well as reflectance and transmittance measurements were performed on high-purity epitaxial InAs grown by metal-organic chemical-vapor deposition. We report the optical identification of excitonic, donor, and acceptor impurity related transitions at a temperature of 1.4 K. Measurements at higher temperature and in the presence of magnetic fields up to 7 T support these identifications. We find the excitonic band gap at 415.65±0.01 meV according to the minimum in the polariton reflectance feature. The donor–acceptor-pair and acceptor-bound exciton transitions for three different acceptors are observed by photoluminescence, and we tentatively associate one of them to a double acceptor formed by a Ga impurity on an As lattice site. A donor-bound exciton transition is observed with a binding energy of 0.42 meV. The magnetic field dependence yields values of the electron effective mass and g factor of (0.026±0.002)m0 and −15.3±0.2, respectively, in good agreement with values obtained by other techniques. Furthermore, we report a deep luminescence band of unknown origin at ∼375 meV, related to drastic temporal changes in the band-edge photoluminescence intensity.