Nanorod-based InGaN/GaN core-shell nanoLEDs

GaN based blue LEDs are the foundation for solid state lighting, which has the potential to approach the theoretical upper efficacy limit of around 500 lumens per watt. GaN is a polar III-V semiconductor with a strong polarization field inside the material depending on the crystal orientation. This strong polarization and piezoelectric field along the polar direction (c-direction) will bend the band structure of the active regions of LEDs and enhance the leakage current under forward bias if MQWs are grown on this polar c-plane. However, the commercial GaN based LED is still grown on the polar c-plane since the nonpolar substrate is highly cost inefficient due to the technology limitations. The nanorod-based LED (nanoLED), which relies on polar c-plane, possess nonpolar m-plane as their sidewalls and therefore are promising to resolve the current difficulties. ❧ In this dissertation, we will discuss in detail the whole procedures involving the nanoLED fabrication, which include substrate pattern preparation required for selective area growth, the n-type nanorod templates, the active region (MQWs) growth, the p-type shell growth, and the 3D p-type contact fabrication. Our prototype nanoLEDs successfully demonstrate light emission under forward bias, but further optimization is still required to fully employ the advantages of their nonpolar-based active region.