skip to main content

Title: Hot electron energy relaxation in lattice-matched InAlN/AlN/GaN heterostructures: The sum rules for electron-phonon interactions and hot-phonon effect

Using the dielectric continuum (DC) and three-dimensional phonon (3DP) models, energy relaxation (ER) of the hot electrons in the quasi-two-dimensional channel of lattice-matched InAlN/AlN/GaN heterostructures is studied theoretically, taking into account non-equilibrium polar optical phonons, electron degeneracy, and screening from the mobile electrons. The electron power dissipation (PD) and ER time due to both half-space and interface phonons are calculated as functions of the electron temperature T{sub e} using a variety of phonon lifetime values from experiment, and then compared with those evaluated by the 3DP model. Thereby, particular attention is paid to examination of the 3DP model to use for the hot-electron relaxation study. The 3DP model yields very close results to the DC model: With no hot phonons or screening, the power loss calculated from the 3DP model is 5% smaller than the DC power dissipation, whereas slightly larger 3DP power loss (by less than 4% with a phonon lifetime from 0.1 to 1 ps) is obtained throughout the electron temperature range from room temperature to 2500 K after including both the hot-phonon effect (HPE) and screening. Very close results are obtained also for ER time with the two phonon models (within a 5% of deviation). However, the 3DPmore » model is found to underestimate the HPE by 9%. The Mori-Ando sum rule is restored by which it is proved that the PD values obtained from the DC and 3DP models are in general different in the spontaneous phonon emission process, except when scattering with interface phonons is sufficiently weak, or when the degenerate modes condition is imposed, which is also consistent with Register's scattering rate sum rule. The discrepancy between the DC and 3DP results is found to be caused by how much the high-energy interface phonons contribute to the ER: their contribution is enhanced in the spontaneous emission process but is dramatically reduced after including the HPE. Our calculation with both phonon models has obtained a great fall in ER time at low electron temperatures (T{sub e} < 750 K) and slow decrease at the high temperatures with the use of decreasing phonon lifetime with T{sub e}. The calculated temperature dependence of the relaxation time and the high-temperature relaxation time ∼0.09 ps are in good agreement with experimental results.« less
Authors:
 [1] ;  [2] ;  [3]
  1. School of Physics, Jilin University, Changchun 130012 (China)
  2. Department of Physics, University of Hull, Hull HU6 7RX (United Kingdom)
  3. School of Computing Science and Electronic Engineering, University of Essex, Colchester CO4 3SQ (United Kingdom)
Publication Date:
OSTI Identifier:
22412848
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM NITRIDES; COMPARATIVE EVALUATIONS; DIELECTRIC MATERIALS; ELECTRON TEMPERATURE; ELECTRON-PHONON COUPLING; ELECTRONS; GALLIUM NITRIDES; HETEROJUNCTIONS; INTERFACES; LIFETIME; PHONONS; POWER LOSSES; RELAXATION TIME; SUM RULES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; THREE-DIMENSIONAL LATTICES