Configurations, energies, and thermodynamics of the neutral MgH complex in GaN.

Journal Article · Sun Jun 01 04:00:00 EDT 2003 · Proposed for publication in Journal of Applied Physics.

OSTI ID:993928

Wright, Alan Francis

Atomic configurations corresponding to local-energy minima for the neutral MgH complex in wurtzite GaN are identified using density-functional theory and the generalized-gradient approximation for exchange and correlation. MgH binding energies, H local-mode vibration frequencies, and configurational degeneracies for the six lowest-energy configurations are used, along with corresponding results for isolated H{sup +}, to compute equilibrium H state populations in Mg-doped GaN as a function of temperature. For a Mg concentration of 1 x 10{sup 19}/cm{sup 3} and a H/Mg concentration ratio of 0.99, MgH is found to be the majority H species at room temperature with isolated H{sup +} becoming the majority species at T {approx} 550 C. Among the MgH states, one is found to dominate at all temperatures. The dominant configuration consists of H at an antibonding site of a N neighbor of the substitutional Mg, with the Mg-N and N-H bonds nearly aligned and the N-H bond oriented at an angle of -109{sup o} with the c axis. The H stretch-mode frequency of the dominant state is consistent with the peak observed in Fourier-transform infrared reflection spectra from Mg-doped GaN samples.

• Research Organization: Sandia National Laboratories
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 993928
• Report Number(s): SAND2003-2451J
• Journal Information: Proposed for publication in Journal of Applied Physics., Journal Name: Proposed for publication in Journal of Applied Physics. Journal Issue: 8 Vol. 94; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
APPROXIMATIONS
CONCENTRATION RATIO
CONFIGURATION
REFLECTION
SPECTRA
THERMODYNAMICS