Exploiting the Negative Polarization Properties of Indium Gallium Nitride (InGaN)/Gallium Nitride (GaN) Heterostructures to Achieve Frequency Doubled Blue-green Lasers with Deep Ultraviolet (UV)

摘要

There is an Army need to develop deep ultraviolet (UV) semiconductor lasers that are compact with a low power budget for use in real-time reagentless biodetection and identification systems as well as water monitoring. Our approach is to develop a visible indium gallium nitride (InGaN) based laser that exploits the negative polarization charge at the heterointerface, which can then be frequency doubled into the deep UV. In the first year of this Director's Research Initiative (DRI), we have developed and tested single heterostructure (SH) n-InxGa1-xN/p-GaN ('p-down') light emitting diodes (LEDs) with 22% In composition and having a peak intensity at 485 nm (blue-green). Under 1% DC, the current injection peaks above 100 A/cm2, well beyond the current density, 10-25 A/cm2, at which conventional p-up, Ga-polar InGaN/GaN multiple quantum well (MQW) LEDs exhibit significant efficiency droop. The achievement of a blue-green LED with reduced efficiency droop at high current densities is a necessary step for achieving a blue-green laser that uses the benefits of the negative polarization charge.