ABSTRACTIn this paper, the optical and electrical properties of both as-grown and annealed thick InxGa1−xNyAs1−y layers grown by metal organic chemical vapour deposition (MOCVD) are presented. Through careful control of the trimetylyindium (TMIn), dimetylyhydrazine (DMHy), trimethylgallium (TMGa) and arsine (AsH3) precursors, lattice matching conditions were achieved for epitaxial layers containing up to 3% nitrogen (0≤y≤0.03) and 11% indium (0≤x≤0.11) with bandgap wavelengths to 1.3 μm. Nomarski optical microscopy and double crystal x-ray diffraction (XRD) measurements are used to investigate surface morphology, material quality and lattice-matched conditions. There is little or no 10K photoluminescence from the as-grown layers; alloy activation through rapid thermal annealing must be performed to obtain observable photoluminescence peaks. Annealing is also performed to reduce the resistivity of the as-grown layers. Once annealed, the undoped layers exhibited p-type carrier concentrations of 5.5×1017 cm−3 and mobilities of 50 cm2/Vs. The DC and frequency response performance characteristics of metal-semiconductor-metal (MSM) photodetectors fabricated on both as-grown and annealed InGaNAs layers are examined and compared to similar structures fabricated using GaAs and InGaAs/InP epitaxial materials.
Enhanced Responsivity of GaN Metal–Semiconductor–Metal (MSM) Photodetectors on GaN Substrate
