Background and Photoexcited Carrier Dependence of Terahertz Radiation from Mg-Doped Nonpolar Indium Nitride Films

Abstract

We report terahertz (THz) generation from Mg-doped nonpolar (a-plane) InN (a-InN:Mg). While the amplitude and polarity of the THz field from Mg-doped polar (c-plane) InN depend on the background carrier density, the p-polarized THz field from a-InN: Mg has background carrier-insensitive intensity and polarity, which can be attributed to carrier transport in a polarization-induced in-plane electric field. A small but apparent azimuthal angle dependence of the THz field from a-InN:Mg shows the additional contribution of the second-order nonlinear optical effect. Meanwhile, in this study, we did not observe the contribution of the intrinsic in-plane electric field which is significant for high stacking fault density nonpolar InN. (C) 2010 The Japan Society of Applied Physics