Optical characterization of Si-doped metamorphic InGaAs with high indium content

The optical properties of Si-doped metamorphic InGaAs layers with electron concentration in the range of 3 × 1016 to 6 × 1018 cm−3 are investigated in detail. The 10 K photoluminescence spectrum of lightly doped metamorphic In0.81Ga0.19As showed a narrow sharp peak at 546 meV with a full width at half maximum of 17.1 meV, comparable to that of InP-lattice-matched In0.53Ga0.47As, which is an evidence of the good crystalline quality. In the temperature range of 10–300 K, only band-to-band transition was observed in both lightly Si-doped In0.53Ga0.47As and In0.81Ga0.19As, while the band-to-band emission was overlapped by multiple transitions in heavily Si-doped In0.81Ga0.19As. A marked blueshift and significant increase in the linewidth of photoluminescence at high doping level were observed due to the enhanced band filling as well as many body effects in the heavily Si-doped high indium content material. The alloy disorder, caused by heavy Si doping, seriously degrades the crystalline quality and immensely reduces the possibilities of radiative recombination in In0.81Ga0.19As.