Towards high sensitivity infrared detector using Cu2CdxZn1-xSnSe4 thin film by SCAPS simulation

Infrared photodetectors have been used widely in various applications. Significant efforts have been made to improve the performance of the commercial infrared photodetectors including HgCdTe and InGaAs for lowering the fabrication cost, simplifying the fabrication processes and increasing the production yield. Cu2CdxZn1-xSnSe4 (CCZTSe) kesterite material is a good candidate for infrared photodetectors application due to its low cost, abundant raw materials on the earth, tunable band gap. The detection rate is an important performance index for infrared detectors, which is inversely proportional to the square root of the dark current, so reducing the dark current is an effective way to improve the detection rate. In order to minimize the dark current and achieve high responsivity and detectivity for CCZTSe thin film infrared detectors (TFID), intermediate layers (between the CCZTSe and back contact) including MoO3, MoSe2 and MoS2 are adpoted and their effect on the performance of the detector are studied via SCAPS-1D (a Solar Cell Capacitance Simulator) software. SCAPS simulation shows that the high-functional MoO3 interfacial layer can reduce the back barrier and dark current of the detector more effectively than the other two. In addition, we find that the carrier concentration of the CCZTSe layer plays a great role on the dark current of the device. The dark current can be reduced significantly to the lowest value when the carrier concentration is 1017 cm−3. Finally, we further predict that the dark current can be reduced to ~ pA/cm2 level, by reducing the back surface recombination and Schottky barrier.