One-pot synthesis, sensitization and photoelectric performance of calcium doped PbSe thin films

Over the past few decades, lead selenide (PbSe) thin films have been widely utilized in infrared photonic devices owing to their narrow band gap, large exciton Bohr radius, high carrier mobility and large dielectric constant. The doping of PbSe thin films has presented an intriguing possibility for tuning their band gap and absorption spectrum range. In this study, we present a “one-step” synthesis of calcium-doped PbSe thin films using the chemical bath deposition method, aiming to address the challenges associated with complex processes and expensive elements. We investigate the effects of dopant concentration on the crystal structure, optical properties, and photoelectric properties. At a dopant concentration of 5 mmol/L, the preferred (200) peak shifts towards higher angle direction. Upon sensitization with iodine, an iodine-rich PbI2 phase forms on the top layer of the film, leading to increased barrier heights and efficient electron trapping within the PbI2/PbSe structure. Furthermore, we study the resistance as a function of illumination duration in pristine PbSe, PbSe-Ca and PbSe-Ca-I. Our results show that the resistance change rate of PbSe-Ca is 8