Electrical, structural, and optical properties of a free-standing 200 lm thick n-type GaN template grown by hydride vapor phase epitaxy have been investigated. Hall mobilities of 1100 and 6800 cm2/V s have been obtained at room temperature and 50 K, respectively. Quantitative analysis of acceptor concentration, donor concentration and donor activation energy has been conducted through simultaneous ®tting of the temperature dependent Hall mobility and carrier concentration data which led to a donor concentration of 2:10 1016 cmÿ3 and an acceptor concentration of 4:9 1015 cmÿ3. The resultant donor activation energy is 18 meV. The analysis indicates that the dominant scattering mechanism at low temperatures is by ionized impurities. The extended defect concentrations on Ga- and N-faces were about 5 105 cmÿ2 for the former and about 1 107 cmÿ2 for the latter, as revealed by a chemical etch. The full width at half maximum of the symmetric (0 0 0 2) X-ray diraction peak was 6900 and 16000 for the Ga- and N-faces, respectively. That for the asymmetric (10±14) peak was 10300 and 14000 for Ga- and N-faces, respectively. The donor bound exciton linewidth as measured on the Ga- and N-face (after a chemical etch to remove the damage) is about 1 meV each at 10 K. Instead of the commonly observed yellow band, this sample displayed a green band, which is centered at about 2.45 eV.
Electrical, structural and optical characterization of free-standing GaN template grown by hydride vapor phase epitaxy
VISCONTI, Paolo;
2000-01-01
Abstract
Electrical, structural, and optical properties of a free-standing 200 lm thick n-type GaN template grown by hydride vapor phase epitaxy have been investigated. Hall mobilities of 1100 and 6800 cm2/V s have been obtained at room temperature and 50 K, respectively. Quantitative analysis of acceptor concentration, donor concentration and donor activation energy has been conducted through simultaneous ®tting of the temperature dependent Hall mobility and carrier concentration data which led to a donor concentration of 2:10 1016 cmÿ3 and an acceptor concentration of 4:9 1015 cmÿ3. The resultant donor activation energy is 18 meV. The analysis indicates that the dominant scattering mechanism at low temperatures is by ionized impurities. The extended defect concentrations on Ga- and N-faces were about 5 105 cmÿ2 for the former and about 1 107 cmÿ2 for the latter, as revealed by a chemical etch. The full width at half maximum of the symmetric (0 0 0 2) X-ray diraction peak was 6900 and 16000 for the Ga- and N-faces, respectively. That for the asymmetric (10±14) peak was 10300 and 14000 for Ga- and N-faces, respectively. The donor bound exciton linewidth as measured on the Ga- and N-face (after a chemical etch to remove the damage) is about 1 meV each at 10 K. Instead of the commonly observed yellow band, this sample displayed a green band, which is centered at about 2.45 eV.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
