Релаксационный спад стимулированного фотонного эха как ключевой параметр оценки условий получения тонкоплёночных активных сред
Authors: Попов И.И. , Юсупов Р.В. , Волков К.А. , Козырев А.Г. , Мальцева С.А. , Мороз А.В. , Петров А.В. 
Published: February 2025

Сообщается о технологических особенностях получения методом магнетронного распыления и функционирования 12 видов исследуемых плёнок, о снятии спектров пропускания оптического излучения этими тонкими плёнками на основе оксида цинка и определении по этим спектрам толщины и количества слоёв плёнок, о результатах исследования топологии поверхности девяти видов тонких плёнок, как трёхслойных, так и двухслойных, полученных на основе оксида цинка с выявлением наиболее приемлемого при их формировании соотношения концентрации кислорода к аргону в камере магнетронного распыления, составляющего 25 к 75 %. Демонстрируется применимость релаксационного спада стимулированного фотонного эха (СФЭ) в плёнках ZnO\Si(B)\Si(P) как метода определения времени релаксации возбуждённых квантовых состояний Т1 и отражения соотношения концентраций газов кислорода и аргона в камере магнетронного распыления, наиболее эффективного с позиции получения наибольшей амплитуды СФЭ, и как метода отражения роли дырок и электронов, инжектируемых с подслоёв легированного кремния в рабочий слой оксида цинка и идентификации вида трионов, возбуждаемых в тонких плёнках при комнатной температуре.

Introduction. The presented study into technologies for obtaining thin-film active media with a wide range of parameters is urgent, that is proved by the facts confirming the possibility of creating nanoelectronic devices based on new physical principles such as a femtosecond time interval recorder, memristor memory on nanoelectronic trion traps in zinc oxide films. The aimof the research was to establish the relaxation decays of the stimulated photon echo of layered structures ZnO\Si(B)\Si(P), which have information about the necessary parameters of the technological process of their production, providing their optical properties used to build nanoelectronic devices based on photon echo. Research methodsinclude probe microscopy, optical spectrophotometry, optical echo spectroscopy with ultrahigh time resolution, adjustment of the magnetron sputtering technology parameters of thin-film layered structures in question, including the ratio of the concentration of oxygen to argon of the working gas mixture in the magnetron sputtering chamber, the sputtering time of layered structures, the composition of layers of thin-film active medium for nanoelectronic devices. The research findingsshowed the presence of various specific dependences of the stimulated photon echo (SPE) decay in layered structures formed at oxygen to argon ratios effective for excitation of echo signals in the working gas mixture in the chamber for magnetron sputtering of layered structures. The irreversible transverse relaxation time T1 was 518 ± 16 fs at the ratio of oxygen to argon concentration in the chamber for magnetron sputtering of 25% to 75%; 516 ± 21 fs at the ratio of 50% to 50%; 740 ± 39 fs at the ratio of 90% to 10%. The most effetive ratios to excite SPE signals were 25% to 75% and 75% to 25%. The study allowed to obtain the dependences of the SPE on the most effective thickness of the layers of the three-layer structure, which inject holes and electrons into the ZnO layer and on the surface topology of the zinc oxide film. In addition to this, it was found that the presence of both types of localized trions (positive and negative) with the dominance of positive trions in the thin-film active medium is obligatory condition. Conclusions.The dependence of the echo signal on the thickness of the injecting 100 nm layers of the three-layer structure was found according to the relaxation decays of the SPE. The longest time of irreversible longitudinal relaxation T1 was not less than 0.74 ps. The intensity of the echo in the ZnO\Si(B)\Si(P) film was close to the sum of the echos formed on purely positive and negative localized trions, with the dominating contribution of positive trions. From the point of view of SPE formation, the most effective ratios of the concentration of oxygen to argon in the working gas mixture in the chamber for magnetron sputtering of films are 25% to 75% and 75% to 25%. The practical significance of the results is manifested in the proposal of relevant methods for monitoring the applied parameters of the technological process that ensure the parameters of active media appropriate for designing new nanoelectronic devices, for instance, femtosecond time interval recorders.