Theoretical analysis of tin incorporated group IV alloy based QWIP

Detailed theoretical investigation on the frequency response, responsivity and detectivity of tin incorporated GeSn based quantum well infrared photodetector (QWIP) is presented in this paper. Rate equation and continuity equation in the well are solved simultaneously to obtained photo generated current. Quantum mechanical carrier transport like carrier capture in QW, escape of carrier from the well due to thermionic emission and tunneling are considered in this calculation. Impact of Sn composition in the GeSn well on the frequency response, bandwidth, responsivity and detectivity are studied. Results show that Sn concentration and applied bias have important role on the performance of the device. Significant bandwidth is obtained at low reverse bias voltage, e.g., 150 GHz is obtained at 0.14 V bias for single Ge0.83Sn0.17 layer. Detectivity, in the range of 107 cm Hz1/2 W−1 is obtained for particular choice of Sn-composition and bias.