Photoluminescence of Ga-face AlGaN/GaN single heterostructures

The radiative recombination in Ga-face Al(0.30)G(0.70)N/GaN single heterost ructures (SHs) was studied by photoluminescence (PL) measurements. An energ y shift of the excitonic transitions toward higher energies was observed, i ndicating the presence of residual compressive strain in the GaN layer. In addition to these exciton lines, a broad band energetically localized betwe en the exciton lines and the LO-phonon replica was noticed in the undoped S H. From its energy position, excitation power dependence, as well as temper ature behaviour, we have attributed this luminescence to the H-band (HB), w hich is representative of the two-dimensional electron gas (2DEG) recombina tion. (C) 2001 Elsevier Science B.V. All rights reserved.