Structure and Photoelectric Properties of PbSe Films Deposited in the Presence of Ascorbic Acid
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ACES, INTERFACES, AND THIN FILMS
Structure and Photoelectric Properties of PbSe Films Deposited in the Presence of Ascorbic Acid L. N. Maskaevaa,b,*, V. M. Yurka, V. F. Markova,b, M. V. Kuznetsovc, V. I. Voronind, and O. A. Lipinac a Ural
Federal University named after the First President of Russia B.N. Yeltsin, Yekaterinburg, 620002 Russia Institute of State Fire Service, Emergency Ministry of Russia, Yekaterinburg, 620022 Russia c Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences, Yekaterinburg, 620990 Russia d M.N. Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, Yekaterinburg, 620108 Russia *e-mail: [email protected] b Ural
Received April 13, 2020; revised April 16, 2020; accepted April 25, 2020
Abstract—Lead selenide thin films produced by hydrochemical deposition with the use of ascorbic acid as an antioxidant of selenourea have been studied by X-ray diffraction analysis, scanning electron microscopy with elemental analysis, and X-ray photoelectron spectroscopy. The effect of the annealing temperature on the elemental composition of the films, their phase composition, crystal lattice parameters, surface morphology, and photoelectric properties has been determined. It is established that, after annealing at 633–683 K, the films contain the PbSeO3, PbSeO4, and PbI2 impurity phases. The optical band gap Eg of the layers in the cases of indirect and direct transitions has been determined. It has been shown that, in terms of their threshold photoelectric characteristics, the deposited films are comparable to widely known commercial samples and can be used to produce highly sensitive infrared detectors. Keywords: chemical deposition, thin films, lead selenide, thermal sensitization, photosensitivity properties DOI: 10.1134/S106378262010022X
1. INTRODUCTION Thin-film lead selenide (PbSe) is a basic semiconductor material that possesses a relatively narrow band gap (0.27 eV at 300 K) and thermoelectric properties and exhibits photosensitivity and luminescence in the infrared (IR) region (1–6 μm). Therefore, this material is in great demand in optoelectronic and sensory technologies [1–3]. As a rule, lead-selenide layers are formed by vacuum evaporation [1, 4–7] and epitaxial methods [8]. However, it is thought that one of the most promising methods is deposition from aqueous media [3, 9–13]. This universal method is distinguished by its simplicity of implementation, the homogeneity of the thin-film coatings produced, the controllability of the process, and the feasibility of varying the electrical properties of the coatings. It is known [3, 9, 12, 13] that the use of selenourea provides the production of PbSe films with better photoelectric characteristics compared to other chalcogenizers; however, the feature that hampers the use of selenourea is its high susceptibility to oxidation in aqueous solutions. The main way to solve this problem is to introduce antioxidants, i.e., substances with a high reducing ability into the solution of selenourea; among such substan
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