High-T Thermodynamics of GaN: A Comparative Study using Mean-Field Theory and Quasiharmonic Debye Model
Volume: 2 - Issue: 08 - Date: 01-08-2013
Approved ISSN: 2278-1412
Published Id: IJAECESTU212 | Page No.: 242-247
Author: N. K. Bhatt
Co- Author: P. R. Vyas,B. Y. Thakore,A. R. Jani
Abstract:-The thermodynamic properties of wide-bandgap semiconductor GaN have been
investigated systematically using the concept of mean-field potential (MFP) approach and
quasiharmonic Debye-model. These properties including volume thermal expansion, isothermal
bulk modulus, Grüneisen parameter, constant pressure and volume specific heats and anharmonic
contribution to ionic specific heat at constant volume are calculated in a wide range of
temperatures (0–2500 K) for cubic zinc-blende (ZB) structure. We have employed nearestneighbour tight-binding second-moment approximation (TB-SMA) to evaluate ambient condition
cohesive properties of GaN. The parameters of the TB-SMA model are derived from the fullpotential linearized augmented plane-wave (FP-LAPW) DFT-approach, obtained within the
generalized gradient condition (GGA). The obtained structural and thermodynamic parameters
under normal condition are found to be in good agreement with the existing experimental and other
theoretical results. Meanwhile, the detailed comparison between the quasiharmonic approximation
(QHA) and anharmonic-MFP models gives insight to the anharmonicity at elevated temperature.
This detailed knowledge of thermodynamic behavior at high–T condition is of fundamental
importance for device applications of GaN
Key Words:-GaN; thermodynamics; mean-field potential; Debye model.
Area:-Engineering
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