XPS Investigation of Indium-Saving Indium–Tin Oxide (ITO) Thin Films

Indium-tin oxide (ITO) thin films with reduced to 50 mass.%indium oxide content are grown by direct current (DC) sputtering of ITO target in mixed argon-oxygen atmosphere onto glass substrates preheated at 523 K.The films showing the best electrical properties are subsequently heattreated in air at temperatures of 523 and 623 K for 60 min.X-ray photoelectron spectroscopy (XPS) and x-ray emission spectroscopy (XES) are used for samples' characterization.Effects of oxygen-flow rate, Sn content, and heat-treatment temperature on electronic properties are studied and discussed.XPS measurements show that indium is in In 3 charge state, and tin is only in Sn 4+ state in indium-saving ITO thin films sputtered at different conditions and heat-treated at different temperatures.As-deposited indium-saving ITO thin film sputtered at 0.5 cm 3 STP /min oxygen-flow rate, which demonstrates the highest conductivity among the as-deposited thin films, shows the highest relative intensity of O II peak.The electron density of states increases when going from indium-saving thin film to typical ITO one.Тонкі плівки оксиду Індію-Стануму (ITO) з пониженим до 50% мас.вмістом оксиду Індію вирощували шляхом розпорошення мішені ITO постійним струмом (DC) у змішаній атмосфері арґону та кисню на скляні підкладинки, попередньо нагріті до 523 К. Плівки, що демон- Наносистеми, наноматеріали, нанотехнології Nanosistemi, Nanomateriali, Nanotehnologii 2022, т. 20, № 2, сс.305-320  2022 ІÌÔ (Іíñòèòóò ìåòàëîôіçèêè іì.Ã. Â. Êóðäþìîâà ÍÀÍ Óêðàїíи) Надруковано в Óкраїні.