An enhancement in the low-field electron mobility associated with a ZnMgO/ZnO heterostructure: The role of a two-dimensional electron gas

作者：Baghani Erfan; O'Leary Stephen K^*

来源：Journal of Applied Physics, 2013, 114(2): 023703.

DOI：10.1063/1.4812492

We determine the role that a two-dimensional electron gas, formed at a ZnMgO/ZnO heterojunction, plays in shaping the corresponding temperature dependence of the low-field electron Hall mobility. This analysis is cast within the framework of the model of Shur et al. [M. Shur et al., J. Electron. Mater. 25, 777 (1996)], and the contributions to the mobility related to the ionized impurity, polar optical phonon, piezoelectric, and acoustic deformation potential scattering processes are considered, the overall mobility being determined through the application of Mathiessen's rule. The best fit to the ZnMgO/ZnO experimental results of Makino et al. [T. Makino et al., Appl. Phys. Lett. 87, 022101 (2005)] is obtained by setting the free electron concentration to 3 x 10(18) cm(-3) and the ionized impurity concentration to 10(17) cm(-3), i.e., within the two-dimensional electron gas formed at the heterojunction, the free electron gas concentration is a factor of 30 times the corresponding ionized impurity concentration. How this enhanced free electron concentration influences the contributions to the low-field electron mobility corresponding to these different scattering processes is also examined. It is found that the enhanced free electron concentration found within the two-dimensional electron gas dramatically decreases the ionized impurity and piezoelectric scattering rates and this is found to increase the overall low-field electron Hall mobility.

• 出版日期2013-7-14