Photoluminescence, reflectance, and magnetospectroscopy of shallow excitons in GaN
- Arizona State Univ., Tempe, AZ (United States)
- Honeywell Technology Center, Plymouth, MN (United States)
- Cree Research, Inc., Durham, NC (United States)
- Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering
The authors report several new aspects of the excitonic properties of heteroepitaxial GaN grown on sapphire or 6H-SiC. In particular, they observed the n = 2 free exciton associated with both A and B excitons (which are distinct from the n = 1 C exciton) using reflectance and 1.7 K photoluminescence. They also studied the behavior of the n = 2 A-exciton using magnetoluminescence in fields up to 12 T. The large diamagnetic shift and splitting positively confirm the identification, yielding an exciton binding energy of about 26.4 meV. Several previous identifications of the n = 2 free exciton yielding a smaller exciton binding energy are probably in error, based on the results. They have also detected the two-electron replica of the neutral donor-bound exciton for the first time in GaN and observed its splitting pattern in magnetic fields up to 12 T. This feature is 22 meV below the principal neutral donor-bound exciton peak, independently of strain shifts in the overall spectrum. It yields a precise donor binding energy of 29 meV for the shallow residual donor in material grown by metalorganic chemical vapor deposition and gas-source molecular beam epitaxy, considerably smaller than that of the residual donor reported earlier in hydride vapor phase epitaxial material (about 35.5 meV).
- OSTI ID:
- 581148
- Report Number(s):
- CONF-961202--; ISBN 1-55899-353-3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Optical spectroscopy of cubic GaN in nanowires
Excitonic recombination processes in undoped and doped wurtzite GaN films deposited on sapphire substrates