Radiative carrier lifetime, momentum matrix element, and hole effective mass in GaN

By using picosecond time-resolved photoluminescence we have measured the lifetime of excess charge carriers in GaN epitaxial layers grown on sapphire at temperatures up to 300 K. The decay time turns out to be dominated by trapping processes at low excitation levels. The radiative lifetime derived from our data is dominated by free excitons at temperatures below 150 K, but also clearly shows the gradual thermal dissociation of excitons at higher temperatures. From our data, we are able to determine the free exciton binding energy and the free carrier radiative recombination coefficient. By combining these data with optical absorption data, we find the interband momentum matrix element and an estimate for the hole effective mass, which is much larger than previously thought.

[1]  Frank Stern,et al.  Spontaneous and Stimulated Recombination Radiation in Semiconductors , 1964 .

[2]  Suzuki,et al.  First-principles calculations of effective-mass parameters of AlN and GaN. , 1995, Physical review. B, Condensed matter.

[3]  S. Nakamura,et al.  InGaN-Based Multi-Quantum-Well-Structure Laser Diodes , 1996 .

[4]  S. Nakamura,et al.  Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure blue‐light‐emitting diodes , 1994 .

[5]  E. Zielinski,et al.  Excitonic transitions and exciton damping processes in InGaAs/InP , 1986 .

[6]  P. Asbeck.  Self‐absorption effects on the radiative lifetime in GaAs‐GaAlAs double heterostructures , 1977 .

[7]  Chang,et al.  Femtosecond dynamics of excitonic absorption in the infrared InxGa1-xAs quantum wells. , 1989, Physical review. B, Condensed matter.

[8]  H. Amano,et al.  Free and bound excitons in thin wurtzite GaN layers on sapphire , 1996 .

[9]  R. J. Nelson,et al.  Minority‐carrier lifetimes and internal quantum efficiency of surface‐free GaAs , 1978 .

[10]  Shun Lien Chuang,et al.  Theoretical prediction of GaN lasing and temperature sensitivity , 1995 .

[11]  R. J. Elliott,et al.  Intensity of Optical Absorption by Excitons , 1957 .

[12]  Theeradetch Detchprohm,et al.  Shallow donors in GaN—The binding energy and the electron effective mass , 1995 .

[13]  Bo Monemar,et al.  Fundamental energy gap of GaN from photoluminescence excitation spectra , 1974 .

[14]  Fernando Ponce,et al.  High dislocation densities in high efficiency GaN‐based light‐emitting diodes , 1995 .

[15]  F. Steuber,et al.  OPTICAL GAIN IN GAINN/GAN HETEROSTRUCTURES , 1996 .

[16]  J. Pankove.  Optical properties of GaN , 1975 .