CC BY
7
УДК 621. 315. 592
Марченко А.В.
доктор физ.-мат. наук, профессор, профессор кафедры физической электроники, Российский государственный педагогический университет им. А.И. Герцена,
Санкт-Петербург, Российская Федерация
Серегин П. П. доктор физ.-мат. наук, профессор, профессор кафедры физической электроники, Российский государственный педагогический университет им. А.И. Герцена,
Санкт-Петербург, Российская Федерация
Доронин В. А.
ассистент кафедры физической электроники, Российский государственный педагогический университет им. А.И. Герцена,
Санкт-Петербург, Российская Федерация
Петрушин Ю. А. магистрант кафедры физической электроники, Российский государственный педагогический университет им. А.И. Герцена,
Санкт-Петербург, Российская Федерация
ЛОКАЛЬНАЯ СТРУКТУРА И АНТИСТРУКТУРНЫЕ ДЕФЕКТЫ ОЛОВА В АМОРФНЫХ И КРИСТАЛЛИЧЕСКИХ ПЛЕНКАХ Ge2Sb2Te5 и Ge1.sAs0.4Tee.1
Аннотация
Методами абсорбционной мессбауэровской спектроскопии на изотопах 119Sn, 121Sb и 125Te показано, что локальная симметрия атомов германия меняется в процессе кристаллизации аморфных пленок Ge2Sb2Te5 и Ge1.5As0.4Te8.! (тетраэдрическая симметрия меняется на октаэдрическую), тогда как окружение атомов сурьмы и теллура не меняется. Методом эмиссионной мессбауэровской спектроскопии на примесных центрах 119mSn, образующихся после радиоактивного распада материнских атомов 119Sb и 119mTe, идентифицированы антиструктурные дефекты олова в узлах сурьмы (мышьяка) и теллура пленок Ge2Sb2Te5 и Ge1.5As0.4Te8.1-
Ключевые слова
Структурные и антиструктурные дефекты, мёссбауэровская спектроскопия, Ge2Sb2Te5 и Ge1.5Aso.4Te8.1.
Marchenko Alla Valentinovna
Doctor of Phys.-Math. Sciences, Professor, Professor of the Department of Physical electronics, A.l. Herzen State Pedagogical University of Russia, St. Petersburg, Russian Federation Seregin Pavel Pavlovich Doctor of Phys.-Math. Sciences, Professor, Professor of the Department of Physical electronics, A.l. Herzen State Pedagogical University of Russia, St. Petersburg, Russian Federation
Doronin Viacheslav Aleksandrovich Assistant of the Department of Physical electronics, A.l. Herzen State Pedagogical University of Russia, St. Petersburg, Russian Federation
Petrushin Yurii Aleksandrovich Master student of the Department of Physical electronics, A.l. Herzen State Pedagogical University of Russia, St. Petersburg, Russian Federation
LOCAL STRUCTURE AND ANTI-STRUCTURAL DEFECTS OF TIN IN AMORPHOUS AND CRYSTALLINE Ge2Sb2Te5 AND Ge1.sAs0.4Te8.! FILMS
Abstract
It was shown by the methods of absorption Mossbauer spectroscopy on the isotopes 119Sn, 121Sb, and 125Te that the local symmetry of germanium atoms changes during the crystallization of amorphous Ge2Sb2Te5 and Ge1.5As0.4Te8.! films (the tetrahedral symmetry does not change to octahedral), while the surroundings of the body of sura atoms. Antistructural defects of tin at the sites of antimony (arsenic) and tellurium in the Ge2Sb2Te5 and Ge1.5Aso.4Te8.1 films have been identified by the method of Mossbauer emission spectroscopy at 119mSn impurity centers formed after the radioactive decay of the parent 119Sb and 119mTe atoms.
Key words
Structural and antistructural defects, Mossbauer spectroscopy, Ge2Sb2Te5 and Ge1.5As0.4Te8.1-
Phase-memory (PM) devices based on chalcogenide semiconductors are mostly used at present for reversible transitions from the amorphous to the crystalline state of thin Ge-Sb-Te films, with the composition Ge2Sb2Te5 attracting most interest. The improvement of PM devices and technology of their fabrication should be based on the results of a study of the crystallization process of amorphous Ge2Sb2Te5 films. Of fundamental importance in these studies is obtaining information about the local structure of an amorphous film and compare it with the crystal structure. It is impossible to describe the PM mechanism without knowing the structural transformations in reversible phase transitions between the amorphous and crystalline states [1,2].
An effective way to examine structural rearrangement in solids is Mossbauer spectroscopy. A key requirement to Mossbauer probes used for these purposes is the possibility of their localization in a certain site of the crystal lattice or in the structural network of the amorphous material. With absorption spectroscopy used to examine the local structure of crystalline and amorphous Ge2Sb2Te5 films, this requirement is satisfied for 119Sn isotope. since tin atoms 119Sn isovalently substitute germanium atoms in the structure of both vitreous and crystalline germanium tellurides [3]. Additionally, it is possible to use emission Mossbauer spectroscopy for the 119mSn isotope with 119Sb and 119mTe mother nuclei. The mother nuclei are certainly introduced into antimony and tellurium sites, respectively. A specific feature of this process is that models of antisite defects are obtained, tin (as an analog of germanium) at antimony or tellurium sites. In this study, we examine the structural rearrangements in Ge2Sb2Te5 films by the above-described absorption and emission procedures. The goal of the study is to obtain information both about the structural rearrangements in the local environment of germanium, antimony, and tellurium atoms in the course of crystallization of amorphous films and about the nature of tin defects in the structure of crystalline films. To interpret the results obtained, we also carry out similar studies of the crystalline and vitreous alloy Ge1.5As0.4Te8.!.
Velocity, mm/s
Fig. 1.
Fig. 2.
Fig. 1. Absorption Mossbauer spectra of 119Sn impurity atoms in amorphous and polycrystalline Ge2Sb2Tes films. The positions of the spectral lines associated with Sn-IV and Sn0 centers are shown.
Fig. 2. Emission Mossbauer spectra of 119mSn impurity atoms formed after the radioactive decay of 119Sb atoms at antimony sites and 119mTe atoms at tellurium sites of a crystalline (hcp-phase) Ge2Sb2Tes film. The positions of the spectral lines associated with Sn2+ and Sn0 centers are shown.
The absorption Mossbauer spectroscopy on 119Sn impurity centers [4] shows that germanium atoms in the structure of amorphous and polycrystalline Ge2Sb2Tes and Ge1.5As0.4Te8.! films have different local symmetries (tetrahedral in the amorphous phase and octahedral in the crystalline) (see Fig. 1). By emission Mossbauer spectroscopy on 119mSn impurity centers formed after the radioactive decay of 119Sb or 119mTe parent atoms, tin antisite defects at Sb (As) and tellurium sites of crystalline Ge2Sb2Te5 and Ge1.5Aso.4Te8.1 films are identified (see
Fig. 2).
References
1. Kolobov A.V. Understanding the phase-change mechanism of rewritable optical media / A.V. Kolobov, P. Fons, A.I. Frenkel, A.I. Ankudinov // Nature Mater. - 2004. - Vol. 3, - p.703.
2. Hu C. All-crystalline phase transition in nonmetal doped germanium-antimony-tellurium films for high-temperature non-volatile photonic applications / C. Hu, Z. Yang, C. Bi, H. Peng // Acta Materialia. - 2020. - Vol. 188. - p. 121.
3. Bobokhuzhaev K. Structural and antistructural defects in chalcogenide semiconductors. Mossbauer spectroscopy / K. Bobokhuzhaev, A. Marchenko, P. Seregin // Academic Pubblishing. - 2020.
4. Серегина Л.Н. Исследование локальной структуры стекол в системах кремний-теллур, германий-теллур и германий-теллур-мышьяк с помощью мёссбауэровской спектроскопии на примесных атомах олова / Л.Н. Серегина, Ф.С. Насрединов, Б.Т. Мелех, З.В. Маслова, и др. // Физика и химия стекла. - 1977. - Т. 3. - с. 328.
© Марченко А.В., Серегин П.П., Доронин В.А., Петрушин Ю.А., 2021
УДК 53.02
В. Е. Федоровский
Пенсионер, физик, бывш. раб. УЭХК, г. Новоуральск, Р.Ф.
О ЗАКОНЕ ВСЕМИРНОГО ТЯГОТЕНИЯ Аннотация
В статье анализируется формула Закона, приводятся результаты наблюдений и экспериментов, которые не объясняются этим Законом; делается вывод о несоответствии Закона реальным физическим процессам, происходящим в природе; предлагается гипотеза о природе гравитации.
Ключевые слова: закон, гравитация, сила, масса, энергия, эфир, частица, волна.
V. E. Fedorovsky
Retired, physicist, former employee of UECC,
Novouralsk, R.F.
ON THE LAW OF UNIVERSAL GRAVITATION Abstract
The article analyzes the formula of the Low; presents the results of observations and experiments that are
