Novel semiconductor materials based on AlN - GaN compounds open up the way for solid-state deep ultraviolet (UV) light sources. Deep UV light emitting diodes (LEDs) with operating wavelengths (l) shorter than 280nm promises revolutionary changes in lighting industry by saving billions of dollars spent for the electricity. Such deep UV LEDs can also be used as compact and portable water, air and food purifiers, biochemical agent detectors (Germicidal applications) and NLOS covert communication. The AlGaN based deep UV LEDs can effectively replace the hazardous and inefficient mercury lamps that also consume huge amount of electricity.

However, the development of highly efficient AlGaN based deep UV emitters must overcome several fundamental problems. The properties of AlGaN materials used for deep UV emission are close to those of typical dielectrics. This makes the doping, contact formation and heat management in these devices extremely difficult. Apart from that, such highly resistive n-AlGaN material causes current crowding problem for conventional square geometry LED design, which limits the device output power.

The main objective of this research work was to study the geometry impact on current crowding and device performance. In order to solve the current crowding problem, a novel geometry micro-pixel LED array design was taken as an approach to achieve high-power deep UV LEDs. In this new design, a conventional large area square diode is split into very tiny micro-pixels.

This PhD dissertation work focuses on the challenges in the fabrication process for micro-pixel LED array design. Fabrication processes such as ohmic contacts, planarization and interconnection were developed as part of this dissertation.

The micro-pixel LED array design developed in this research was proved to be very successful for current crowding elimination. As a result a large area, low resistance high power sub-280 nm deep UV LEDs was attained. Using this new design a world record milliwatt on-wafer optical power at 280nm emission wavelength has been achieved.