Design and Modeling of High Efficiency III Nitride Planar and Nanowire LEDs for Emerging Optoelectronics Applications

Abstract

The limitations in scaling incandescent light source devices have prompted the exploration of alternative technologies. One such promising device is the light-emitting diodes (LEDs), which has garnered significant research attention. LEDs have many advantages over conventional light sources due to their low power consumption, small size, and lengthy lifespan. The development of LEDs with excellent efficiency and great brightness was made possible in the recent years because of the group III-nitride materials. With energies ranging from 0.7 eV (InN), 3.4 eV (GaN) to 6.2 eV (AlN) IIInitrides and their alloys are particularly well suited for visible and ultraviolet LEDs. GaN and its alloy-based blue LEDs are the most well-known example and they have completely changed the modern light technology. Studies reveal that the band gap for GaN varies from 3.47 to 3.239 eV over a temperature range of 0-600K which corresponds to a wavelength variation of 357.3 to 382.8 nm (UV/visible range), making GaN a versatile material for fabricating white LEDs. Thus the semiconductor devices fabricated with GaN are good options compared to Si, SiC, and GaAs due to its high thermal conductivity. Nitride semiconductors are the best materials for realizing optical devices in the UV, visible and infrared (IR) regime. Additionally, Group-V elements are the smallest and most electronegative elements with metal-N bond that have far higher iconicity than other III-V bonds. The thesis reports design, modelling, simulation and analysis of novel III-Nitride nanowire LED structure. To understand the impact of dimensionality and other electrical parameters on this LED structure, TCAD simulations with calibrated models are performed. The structure offers unique benefits due to their novel design and material modifications and all the characteristics are compared with the experimental results of fabricated LED. newline