Manipulative Polarization of a-plane InGaN/GaN Photonic Crystals for Enhanced Spontaneous Emission (original) (raw)

2010, Extended Abstracts of the 2010 International Conference on Solid State Devices and Materials

Introduction Recently, Ⅲ-nitride-based optoelectronic devices, such as InGaN/GaN laser diodes have been used for various applications, including BD players, overhead projectors, and laser printers. However, for a c-plane InGaN/GaN quantum well (QW), there exists a strong build-in electric field due to the accumulation of spontaneous and piezoelectric polarization charges at the interface, leading to the quantum-confine Stark effect (QCSE). To avoid the internal field, the growth of non-polar InGaN/GaN quantum wells along (112 0) direction (a-plane), or along (11 00) direction (m-plane) 1 has garnered intensive research interests. As a result of eliminating QCSE, the non-polar light emitting sources exhibit not only high internal quantum efficiency, but also strong polarization 2 , which must be taken into account for device design. The development of threshold-less lasers have been proposed by raising the spontaneous emission rate through a photonic crystal (PC) microcavity with a high quality factor (Q-factor) and a small modal volume (V m) 3,4. However the design of PC microcavities mainly focuses on the value of Q/V m , which was proposed by Purcell 5 first in 1968. In the ideal case, the polarization of cavity modes is assumed to be aligned with the polarization of electric charges, which is not true for strongly y-polarized emission from a-plane InGaN/GaN QWs. In this work, we demonstrate the enhanced spontaneous emission (SpE) from an a-plane InGAN/GaN QW by optimizing Q, V m , and polarization properties of a PC microcavity slab using a finite difference time domain (FDTD) approach. The enhancement factors where the spontaneous emission coupled to the dominant cavity modes are calculated and investigated for different quantum well thicknesses and Indium compositions.