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A Rapid Thermal Annealing (RTA) system was used to anneal sputtered and MOVPEgrown Aluminum Nitride (AlN) thin films at temperatures up to 1000°C in ambient and controlled environments. According to Energy Dispersive X-Ray Analysis (EDAX), the films annealed in an ambient environment rapidly oxidize after five minutes at 1000°C. Below 1000°C the films oxidized linearly as a function of annealing temperature which is consistent with what has been reported in literature [1]. Laser Doppler Vibrometry (LDV) was used to measure the piezoelectric coefficient, d 33 , of these films. Films annealed in an ambient environment had a weak piezoelectric response indicating that oxidation on the surface of the film reduces the value of d 33 . A high temperature furnace has been built that is capable of taking in-situ measurements of the piezoelectric response of AlN films. In-situ d 33 measurements are recorded up to 300°C for both sputtered and MOVPE-grown AlN thin films. The measured piezoelectric response appears to increase with temperature up to 300°C possibly due to stress in the film.

Resonant cavity light emitting diode (RCLED) structure was grown using digital AlGaN/GaN Distributed Bragg Reflector (DBR) and Ag-based p-contact. A five period of InGaN/GaN multi-quantum well (MQW) layers are placed between these two high reflectance mirrors. Digital AlGaN/GaN DBR have a maximum reflectivity of about 60 % at 445 nm and 90 % at 439 nm for 6 period and 12 period, respectively. Ag-based p-contact exhibits an average reflectance of around 85-90 % for a wavelength of 400-600 nm. The light output intensity of the RCLEDs with 12 period digital AlGaN/GaN DBR is higher by a factor of 3 as compared to that of the similar structure without digital AlGaN/GaN DBR at an injection current of 50 mA.

Group III nitride wide band gap semiconductors have recently attracted considerable attention due to their applications for optical devices operating in the blue and UV wavelength regions. Nitride materials are stable at high temperatures and also chemically stable. Analysis of InGaN based blue laser diodes is required for the research and development of future deep UV laser diodes for bio-sensing applications. The conventional multiple quantum wells suffer from inhomogeneous carrier distribution across quantum wells. This inhomogeneous distribution increases the threshold current density of the laser diode. This project addresses the issue through the design of a novel structure for the active region of InGaN blue laser diodes. As a possible replacement for the AlGaN cladding layers optical properties of a 1D photonic crystal was investigated. Part of the work deals with the etching of GaN in SF 6 plasma using ICP-RIE systems.