Study of polarization properties of light emitted from a-plane InGaN/GaN quantum well-based light emitting diodes

This paper discusses the optical characteristics of a nonpolar a-plane InGaN/GaN quantum well with different indium compositions, quantum well widths, and injection carrier densities. The self-consistent Poisson and 6 x 6 k.p Schrodinger solver has been applied to study the band structures in nonpolar a-plane InGaN-based quantum well light emitting diodes (LEDs). We find that the larger indium composition and smaller well width make the energy separation of vertical bar Y >-like state to vertical bar Z >-like state larger, and as a result enhance the polarization ratio of light. However, the polarization ratio decreases as the carrier injection increases, which might be a drawback for high power applications. We have studied the optimization condition for designing the a-plane InGaN quantum well LED for applications, such as liquid crystal display backlight modules and lasers, which would be useful information for device designs. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3176964]