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Deep ultraviolet emission from ultra-thin GaN/AlN heterostructures

2016; American Institute of Physics; Volume: 109; Issue: 24 Linguagem: Inglês

10.1063/1.4971968

1520-8842

Dylan Bayerl, S. M. Islam, C.M. Jones, Vladimir Protasenko, Debdeep Jena, Emmanouil Kioupakis,

Photocathodes and Microchannel Plates

We present the theoretical and experimental results for the electronic and optical properties of atomically thin (1 and 2 monolayers) GaN quantum wells with AlN barriers. Strong quantum confinement increases the gap of GaN to as high as 5.44 eV and enables light emission in the deep-UV range. Luminescence occurs from the heavy and light hole bands of GaN yielding E ⊥ c polarized light emission. Strong confinement also increases the exciton binding energy up to 230 meV, preventing a thermal dissociation of excitons at room temperature. However, we did not observe excitons experimentally due to high excited free-carrier concentrations. Monolayer-thick GaN wells also exhibit a large electron-hole wave function overlap and negligible Stark shift, which is expected to enhance the radiative recombination efficiency. Our results indicate that atomically thin GaN/AlN heterostructures are promising for efficient deep-UV optoelectronic devices.