Polarized Light Emission from Nonpolar InGaN Light-Emitting Diodes Grown on a Bulk m-Plane GaN Substrate

摘要

Polarized light emission from (1010) m-plane InGaN/GaN light-emitting diodes has been observed and analyzed in relation to the valence band structure in nonpolar InGaN/GaN quantum wells. Electroluminescence along the < 1100 > direction out of the m-plane was partially polarized in the < 1120 > direction, with a polarization ratio of 0.17. This polarized light emission exhibited a spectral peak at 2.69 eV, which has been attributed to the transition between the conduction band and the heavy hole subband with p_x atomic orbital-like character due to the inhomogeneous biaxial strain in the device structure. Weak polarized emission in the < 0001 > direction was also observed, with a spectral peak at the higher energy of 2.78 eV. The transition between the conduction band and the crystal-field split-off subband is believed to be responsible for the < 0001 > polarized light emission.