Investigation of LiF Interlayer on Charge Collection Efficiency and Leakage Current in CsPbBr₃Radiation Detector

CsPbBr3 (CPB) single crystal has exhibited remarkable photoelectric properties and great potential for radiation detection. However, the applications are still challenging for the limited bulk resistivity and the chemical reactivity of electrode contacts. A metal-insulator-semiconductor structure of In/LiF/CPB is employed to modify the contact characteristics. By introducing a LiF interlayer, the interface trap density of detector is tuned to as low as 2.80× 108 cm-2 eV-1, compared to 2.42× 109 cm-2 eV-1 of In/CPB/Au detector, which is attributed to the block of diffusion and reaction between metal and crystal. The barrier height of In/LiF/CPB/Au device is increased to 0.66 eV and the leakage current falls to 85.7 nA cm-2 under an electrical field of 1000 V cm-1. The In/LiF/CPB/Au device exhibits superior photoresponse ON/OFF ratio and energy resolutions of α -particles (241Am at 5.48 MeV) and γ-rays (241Am at 59.5 keV and 137Cs at 662 keV) than the In/CPB/Au device, suggesting that the introduction of LiF interlayer is a simple yet effective method to improve the performances of CPB Schottky junction radiation detector.