Quantum corrections to the electrical conduction in an AlGaN/GaN heterostructure

Citation
Z. Dziuba et al., Quantum corrections to the electrical conduction in an AlGaN/GaN heterostructure, APPL PHYS A, 72(6), 2001, pp. 691-698
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
ISSN journal
0947-8396 → ACNP
Volume
72
Issue
6
Year of publication
2001
Pages
691 - 698
Database
ISI
SICI code
0947-8396(200106)72:6<691:QCTTEC>2.0.ZU;2-9
Abstract
A new method for magneto-transport characterisation of semiconductor hetero structures is presented. The classical model of mixed conduction, modified by corrections resulting from quantum effects, has been used in the analysi s of the conductivity-tenser components, magnetoresistance, and Hall coeffi cient in n-type Al0.85Ga0.15N/GaN in magnetic fields up to 12 T, in the tem perature range from 2 to 295 K. The mixed conduction is due to high-mobilit y carriers in the conduction band in the interface and to low-mobility carr iers in the conduction band in the GaN layer and in an impurity band. The c orrections to the conduction of high-mobility carriers result from quantum effects: negative magnetoresistance, extraordinary Hall effect, and freeze- out of electrons. Negative magnetoresistance is due to localisation of elec trons and to increasing tunnel coupling between electron states in differen t minima of a random potential, due to interface roughness. The extraordina ry Hall effect has been explained by interaction of electrons with magnetic moments of dislocations in the interface. Decreasing concentration of elec trons is probably due to Landau quantisation of the conduction band in the interface of the heterostructure.