Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1814988 | Physica B: Condensed Matter | 2007 | 4 Pages |
Abstract
Results of isochronal annealing up to a temperature of 660Â K of n-type GaAs grown by low-pressure metal organic chemical vapor deposition (LP-MOCVD) are reported. Deep-level transient spectroscopy (DLTS) reveals EL2 as the only electron-emitting deep-level defect in our as-grown material, whereas three hole-emitting levels at Ev+0.09Â eV, Ev+0.40Â eV and Ev+0.93Â eV are observed in the minority-carrier injection spectra. While yielding interesting results on the behavior of these pre-existing deep-level defects, thermal annealing is found to introduce at least four new defects, three in the upper half of the band gap at Ecâ0.13Â eV, Ecâ0.16Â eV and Ecâ0.36Â eV, and one in the lower half at Ev+0.19Â eV. Two of these defects, one at Ecâ0.16Â eV and the other at Ecâ0.36Â eV, are identified with previously reported annealed-in deep levels in n-GaAs, while the other two defects cannot be identified with any of the deep levels reported in the literature. Data on the annealing behavior and other characteristics of these annealed-in levels are presented. All the pre-existing inadvertent deep-level defects in the as-grown material were found to be stable up to 600Â K, beyond which the minority-carrier emitting levels start to anneal out, but EL2 tends to show a slight increase with annealing temperature.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Nazir A. Naz, Umar S. Qurashi, M. Zafar Iqbal,