Determination of the electron trap level in Fe-doped GaN by phonon-assisted conduction phenomenon
Hiroki Fukuda, Akira Nagakubo, Shigeyoshi Usami, Masashi Ikeda, Masayuki Imanishi, Masashi Yoshimura, Yusuke Mori, K. Adachi, Hirotsugu Ogi
Abstract
Abstract We acoustically measured the energy level for thermally activated conduction (TAC) in high-resistivity Fe-doped GaN using the non-contacting antenna-transmission acoustic-resonance method. The acoustic attenuation takes a maximum at a specific temperature, where the TAC is accelerated with the help of phonon energy. The Debye-type relaxation is thus observed for acoustic attenuation, and its activation energy (0.54 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>±</mml:mo> <mml:mspace width=".25em"/> </mml:math> 0.04 eV) was determined with attenuation measurements at various frequencies and temperatures. This value agrees with the E3 level in GaN, indicating that thermally associated conduction originates from the E3 trap level. We also measured the five independent elastic constants at high temperatures.