Two-dimensional electron gas and persistent photoconductivity in heterostructures
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
8
Pages
13793-13798
Date Issued
2018
Author(s)
Lin, T.
Abstract
We present results of electrical and optical measurements in an (Formula presented) heterostructure. The presence of a two-dimensional electron gas at the high-quality (Formula presented) heterointerface is confirmed by Shubnikov-de Haas measurement, which shows well-resolved magnetoresistance oscillations starting in fields below 3 T at 1.3 K. From the temperature dependence of the oscillation amplitude, the obtained effective mass (Formula presented) is in excellent agreement with the value of cyclotron resonance measurements in two-dimensional (2D) systems, but larger than the values of theoretical and experimental results in GaN bulk films. We point out that the effective-mass enhancement in 2D systems is due to the effects of band nonparabolicity and wave-function penetration into the barrier material. The results of photoconductivity measurements reveal that persistent photoconductivity (PPC) does exist in the (Formula presented) heterostructure, and that the PPC behavior of (Formula presented) heterojunction is quite different from that of the GaN epitaxial thin films. A possible mechanism is presented to interpret the observed PPC effect. © 1998 The American Physical Society.
Type
journal article