Polycrystalline lead selenide prepared by an oxygen ion beam induction

Manipulating optical and electrical properties is promising for applications such as photodetectors and solar cells. Comparing with chemical preparation methods, tuning optical and optoelectronic properties by physical vapor phase methods has extra merits such as large area uniformity and CMOS compatibility. An in situ oxygen ion beam preparation method with an ion beam modulation is demonstrated for lead selenide. Polycrystalline lead selenide thin films with tunable optical band gap and low structural disorder have been fabricated using an orthogonal experimental scheme. The morphological evolution between three specific microstructures, mainly governed by ion energy and annealing temperature, has been observed. The structural characterizations indicate the presence of some oxides phases and crystallite size of hundreds of nanometers. The more suitable optical band gap within 0.75-1.1 eV was obtained at room temperature for absorption of mid-infrared photons. The ultra-low Urbach energies suggest a structurally well-ordered microstructure. The dependences of the structural, electrical and optical properties on the preparation parameters have been revealed by range analysis, indicating the main role of ion energy in the manipulations of these properties. Ion energy and beam current were revealed to be more sensitive in affecting optoelectronic properties, and the manipulation effects were demonstrated to be long wavelength sensitive. These results provide an attractive approach to manipulate and optimize the structural, electrical and optical properties of polycrystalline lead chalcogenides in mid-infrared optics and optoelectronics. (C) 2020 Elsevier B.V. All rights reserved.