Laser pulse tuning for optimized photodetector performance in CsPbI3/Si heterojunctions

Abstract

Cesium lead iodide (CsPbI₃) is a promising material for optoelectronic applications due to its high absorption coefficients, long carrier diffusion lengths and tunable energy gap. This study investigates the influence of the number of laser pulses on the structural, optical and electrical properties of CsPbI₃ films deposited on silicon substrates by pulsed laser deposition (PLD). X-ray diffraction and scanning electron microscopy analysis shows that increasing the laser pulses from 40 to 130 leads to an improvement in the crystallinity of the films, transforming isolated crystallites into a dense interconnected network. Optical characterization shows that films deposited with 100 pulses have an ideal band gap of 2.4 eV. Hall effect measurements show that films with 70 pulses have the highest carrier mobility of 25 cm²/Vs, while films with 100 pulses achieve a balance between a high carrier concentration of 1.2 × 10¹⁸ cm^− 3 and a low resistivity of 5 × 10^− 5 Ω.cm, indicating optimal electrical properties. The CsPbI₃/Si photodetectors fabricated with 100 pulses show excellent performance with responsivity of 6.7 A/W, a detectivity of 1 × 10¹² Jones and a quantum efficiency of 12 × 10²% at 600 nm. This work demonstrates the importance of optimizing the PLD laser pulses to control the film properties for high performance photodetectors.