Thermal Activation of Iodine-Containing PbSe thin Films

Abstract

Influence of iodine addition on elemental composition, structure and surface morphology on lead selenide thin films prepared by chemical bath deposition method was studied by methods of X-ray diffraction analysis and scanning electron microscopy with elemental energy-dispersive analysis. Content of iodine in thin films raised to 4.25 at.% with increasing concentration of ammonium iodide in bath solution. Influence of anneal on structure and crystallite size of lead selenide thin films was found.Keywords: chemical bath deposition, thin films, lead selenide, iodine doping, annealing, thermal activation, X-ray diffraction, scanning electron microscopy, doping, semiconductors Introduction Thin films based on lead chalcogenide are one of the most promising semiconductor material. Lead chalcogenides have high photovoltaic properties in spectral range from 2.0 to 5.0 micrometer, due to they have been found wide applications in photodetector [1].Both physical and chemical methods of deposition have been used for prepare lead chalcogenide. Thermal evaporation technique [1][2][3][4] and chemical bath deposition [1,[5][6][7] are the most popular method which permit to obtain polycrystalline materials providing a different structure and physical properties. The chemical bath deposition method is low-cost processes and the films are of comparable quality to those obtained by more complicated and expensive physical deposition processes. It can be used for preparation of high-quality lead chalcogenide films with control of the deposition parameters such as stirring period, reaction time, bath temperature, solution pH, and added impurities.As-deposited thin films also don't have photosensitivity because they are subject to hightemperature annealing in an oxygen atmosphere. Changing the conditions of thermal activation, it can also affect the photovoltaic properties of materials [8]. Alloy addition may occur both during the synthesis of the films and during annealing. Iodine-containing additions use in the chemical deposition of thin films because the iodine provides with high sensitive to IR radiation [2,3,5,6].