New Approach of III-Nitride Epitaxy and the Fabrication of White LEDs

The applications of nitride family are extended to the spectral region appropriate to fiber optics communication and photovoltaic applications since InN was found recently to be a narrow gap semiconductor. The method of film deposition is therefore an important key to the breakthrough of the devices performance. A novel method was demonstrated first time for the epitaxy of III- Nitride materials. The active nitrogen was produced in the form of clusters containing approximately 2000 nitrogen molecules. The clusters were singly or doubly ionized with positive charge by electron impact and accelerated up to approximately 20 to 25 KV prior to their disintegration on the substrate. Due to the high local temperature produced during the impact of clusters with the substrate, this method is suitable for the deposition at very low temperatures. The fabrication of white light LEDs without the use of phosphor can possibly boost the efficiency. The results are demonstrated with the formation of LED structures on textured GaN templates produced by either hydride vapor phase epitaxy (HVPE) or using a method of natural lithography and reactive ion etching.