Optical Spectroscopy of Mg- and C-Related Donor and Acceptor Levels in GaN Grown by MBE

✍ Scribed by S. Strauf; P. Michler; J. Gutowski; U. Birkle; M. Fehrer; S. Einfeldt; D. Hommel

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 173 KB
• Volume: 216
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/(sici)1521-3951(199911)216:1<557::aid-pssb557>3.0.co;2-4

✦ Synopsis

We present photoreflectance (PR) in combination with temperature and density dependent photoluminescence (PL) on undoped as well as on Mg-and C-doped GaN grown by molecular beam epitaxy (MBE). We determined the binding energy of the free A-exciton, the residual donorbound exciton and the Mg-acceptor-bound exciton to (26 AE 1), (5 AE 1) and (18 AE 1) meV, respectively. In n-type GaN a residual DAP band appears independent of the particular type of dopant. Free-hole concentrations up to 10 18 cm ± ±3 in MBE grown p-GaN:Mg were achieved without generation of deep compensating donors. Moreover, we found evidence for a second DAP series involving a shallow compensating donor level built in along with Mg doping. The correlation of different DAP bands to the respective type of conductivity opens an alternative way to control the p-type doping in GaN:Mg without the need for electrical contacting.