Low temperature deposition of vanadium dioxide on III–V semiconductors and integration on mid-infrared quantum cascade lasers

We demonstrate low temperature deposition conditions for vanadium dioxide (VO₂) phase change material by pulsed laser deposition, which are compatible with III–V semiconductors heterostructures typically used in optoelectronic applications. The characterizations of the VO₂ coated thin films grown on GaAs show a 50% change in optical reflectivity in the mid-infrared range and a variation of electric conductivity of two orders of magnitude between the insulating (low temperature) and the metallic (high temperature) states. The transition temperature is estimated around 68 °C (341 K). We also study the functionalization of mid-infrared quantum cascade lasers (QCLs) (operating at wavelengths λ ∼ 7–8 μm) with VO₂ layers, in view of engineering the laser emission properties with an integrated VO₂ layer. We demonstrate QCLs that integrate a VO₂ layer on the surface that interacts with the guided laser mode. A maximum operating temperature of 61 °C (334 K) has been measured.