Electrically-Pumped III-Nitride Intersubband lasers

Kyma Technologies together with the two subcontractors at Princeton University and Lehigh University aim to develop III-Nitride QCL at near 1.55 µm based on native GaN substrates and strain-compensation heterostructures engineering. We intent to employ new approaches, aiming to overcome the challenges in realization intersubband emission in III-Nitride structures. High quality native GaN substrates with low dislocation density with both polar and nonpolar surface orientations will be considered. Optimization of surface polishing and surface off-cut orientation are expected to enhance the structural quality and interface smoothness of the device structures. In Phase I proposal we will design (Al,Ga)N/GaN device structures accounting for or excluding the polarization fields in the devices grown along polar or nonpolar directions, respectively. Also, design of strain-free AlInGaN/GaN device structure will be elaborated and analysis of limiting theoretical factors will be performed. Epitaxial growth of (Al,Ga)N/GaN MQW structures grown by MOCVD on bulk GaN substrates is intended with a demonstration of intersubband absorption at near 1.55 µm. We will characterize the structures and will analyze the limiting experimental factors involved in producing intersubband transitions. It will allow us to estimate the best approach towards realization of intersubband laser at 1.55 µm intended for Phase II program.