A first-principles-derived method for computing the piezoelectric coefficients of complex semiconductor Sc1−xGaxN alloys
✍ Scribed by A. Alsaad; A. Ahmad; H. Alta’ani; R. Alshyab
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 358 KB
- Volume
- 403
- Category
- Article
- ISSN
- 0921-4526
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✦ Synopsis
First-principles methods
Piezoelectric coefficients e 33 Macroscopic strain Elastic response Ordered Sc 1Àx Ga x N alloys Disordered Sc 1Àx Ga x N alloy a b s t r a c t
We use direct first-principles techniques and Keating's semiempirical valence force field (VFF) approach to develop a first-principles-derived method to calculate the piezoelectric coefficients e ij of semiconductor heterostructures and alloys. This technique is applied to study the effect of the atomic arrangement and composition on e 33 piezoelectric coefficients of hexagonal ordered and disordered Sc 1Àx Ga x N alloys. Our results on ordered structures are in excellent agreement with local density approximation (LDA) first-principles calculations. Our results reveal that atomic ordering can have a large effect on piezoelectricity and that e 33 of ordered and disordered Sc 1Àx Ga x N alloys as a function of Ga concentration can be fitted into a fourth-order and a fifth-order polynomial, respectively. Results of this work are predicted to have a large impact on improving the quality of Sc 1Àx Ga x N alloys and heterostructures grown on ScN substrates. The microscopic origins for these effects are discussed and explained in detail.