Intersubband absorption in m-plane ZnO/ZnMgO MQWs

ZnO has great potential for devices in the mid IR and the THz range through the use of intersubband (ISB) transitions in multiple quantum wells (MQWs), although exploiting these transitions requires great control of the epitaxial layers as well as of the physics involved. In this work we present an analysis of non-polar ZnO grown homoepitaxially by molecular beam epitaxy on m-plane ZnO substrates as an ISB optical absorber. The MQWs were characterized under a 45°-bevelled multi-pass waveguide configuration allowing the observation at room temperature of an ISB transition in the 4-6 μm region for p-polarized incident light.