Abstract
Effects of AlxGa1-xN/GaN superlattice (SL) insertion on the structural homogeneity, photoluminescence (PL) lifetime, and defect densities were studied in cubic (c-) GaN epilayers on (001) GaAs substrates grown by low-pressure metalorganic vapor-phase epitaxy. Values of the full-width at half-maximum (FWHM) of both the (002) X-ray diffraction peak and near-band-edge excitonic PL peak were decreased by a factor of 2, and the room-temperature PL intensity was improved by a factor greater than 10 through the use of double 15-period 3,8-nm-thick Al0.35Ga0.65N/2. 5-nm-thick GaN SL layers between the c-GaN epilayer and the c-GaN template layer prepared on a substrate-decomposition-shielding GaN layer deposited at a low temperature. The density or size of Ga-vacancy (V Ga)-related defects in the c-GaN epilayer was also significantly reduced, and simultaneous increase in the excitonic PL lifetime at 293 K from approximately 20 ps to 230 ps indicated a tremendous reduction of the nonradiative defect density.
Original language | English |
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Pages (from-to) | 481-488 |
Number of pages | 8 |
Journal | Journal of Crystal Growth |
Volume | 272 |
Issue number | 1-4 SPEC. ISS. |
DOIs | |
Publication status | Published - 2004 Dec 10 |
Externally published | Yes |
Keywords
- A1. Positron annihilation
- A3. Metalorganic vapor phase epitaxy (MOVPE)
- A3. Superlattice (SL)
- B1. I GaAs substrate
- B1. Nitrides
- Bl. Cubic GaN
ASJC Scopus subject areas
- Condensed Matter Physics
- Inorganic Chemistry
- Materials Chemistry