Growth and deep ultraviolet picosecond time-resolved photoluminescence studies of AlN/GaN multiple quantum wells

AlN/GaN multiple quantum wells (MQWs) with a well thickness of 26 Angstrom have been grown by metal-organic chemical-vapor deposition. A specially des igned photoluminescence (PL) spectroscopy system, which is capable of measu ring picosecond time-resolved PL up to 6.2 eV, has been employed to probe t he optical properties as well as the carrier transfer and decay dynamics in these MQWs. Optical transitions at 4.039 and 5.371 eV at T=10 K, resulting from the interband recombination between the electrons and holes in the n= 1 and n=2 subbands in the wells, have been observed. The band-offset parame ter for the AlN/GaN heterostructure has been obtained by comparing the expe rimental results with the calculations. Carrier dynamics including the rela xation of the electrons and holes from the n=2 and n=1 subband in the condu ction and valence bands and the decay lifetimes of the interband transition s have also been measured and analyzed. Detailed subband structures for bot h the conduction and valence bands in the wells were determined. The implic ations of our findings on the potential applications of AlN/GaN quantum wel ls have been discussed. (C) 2001 American Institute of Physics.