Abstract
A sinusoidal dependence of the s- and p-polarized terahertz (THz) emission on sample rotation angle in m- and a-plane InN has been observed using ultrafast pulse excitation at a moderate pump fluence of ∼1 µJ/cm2. The angular dependence is attributed to carrier drift in an intrinsic in-plane electric field parallel to the c-axis induced by stacking fault-terminated internal polarization at wurtzite domain boundaries, with a THz polarity flip corresponding to a reversal of the c-axis. The p-polarized THz signal also consists of an angular-independent component, similar to that from c-plane InN, consistent with surface normal transport due to the photo-Dember effect.