Abstract
Room-temperature photoluminescence has been studied in n -type bulk ZnO crystals representing three different growth methods and having free-carrier concentrations (n) ranging from 1013 to 1018 cm-3. The near-band-edge emission has both free-exciton and free-exciton-phonon contributions, with the strength of the phonon coupling dependent on sample defect concentrations. Band-gap shrinkage effects are used to explain a decrease in emission energy for the higher n values. Band filling and band nonparabolicity are predicted to be important for n > 1019 cm-3. At 300 K, in the absence of free carriers, the free-exciton energy is 3.312±0.004 eV.
| Original language | English |
|---|---|
| Article number | 251906 |
| Journal | Applied Physics Letters |
| Volume | 89 |
| Issue number | 25 |
| DOIs | |
| State | Published - 2006 |
Funding
This work was supported at WVU by NSF Grant No. DMR-0508140. Work at the ORNL Center for Radiation Detection Materials and Systems was supported by the NNSA Office of Nonproliferation Research and Engineering (NA-22), U.S. DOE, and by the Department of Homeland Security, Domestic Nuclear Detection Office. ORNL is operated by UT-Battelle, LLC under DOE Contract No. DE-AC05-00OR22725.