Photoluminescence and electrical characteristics of the two-dimensional electron gas in Si delta-doped GaN layers

We have studied the electrical and photoluminescence (PL) properties of a S i delta-doped GaN layer grown by metalorganic chemical vapor deposition. Th e Hall mobility and electron sheet concentration are 726 cm(2)/V s and 1.9x 10(12) cm(-2), respectively, at 2 K. A PL peak located at 78 meV below the band gap of GaN is observed at 77 K. This PL peak is attributed to the radi ative recombination between electrons in the two-dimensional quantum states and photoexcited holes in GaN, which is consistent with simulation results using a one-dimensional Poisson and Schrodinger equation solver. The peak disappears at temperatures higher than 77 K and is not observed in uniforml y doped GaN layers. (C) 2001 American Institute of Physics.