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Information × Registration Number 0218U001092, 0115U004262 , R & D reports Title "Experimental and theoretic studies of electrical and microwave properties of nanostructures and electronic devices based on the wide-gap semiconductor materials" popup.stage_title Head Belyaev Alexander, Доктор фізико-математичних наук Registration Date 18-01-2018 Organization Institute of Semiconductor Physics popup.description2 The purpose of the stage is to determine the influence of deformations on the structural and optical characteristics of heterostructures (HS) with GaN / AlN superlattices (SL) grown on GaN / Al2O3 substrates (0001). The research methods - electron microscopy, X-ray diffractometry, micro-Raman, photoluminescence and infrared Fourier spectroscopy. It is established that with increasing number of periods in HS with GaN / AlN superlattices the structural quality of the composite layers of SL is significantly improved, the boundaries between the layers become more sharp at the atomic level, mechanical stresses in GaN layers increase, and the relaxation occurs in barrier AlN layers. It is shown that with increasing number of SL periods, optical radiation from GaN quantum wells is significantly shifted to the red part of the spectrum (from 3.28 eV for the 5-period structure to 3.18 eV for the 20-period structure), below the band gap of GaN, due to quantum confined Stark effect. The dependence of the energy of the photoluminescence peaks on the number of SL periods is in good agreement with the results of the Raman spectroscopy and X-ray diffractometry studies and shows that the dominant influence on the energy of optical interband transitions in GaN quantum wells is the strain in SL layers. In the study of the dependence of the phonon frequency on stress in SL, the phonon deformation potentials a and b for E2H and ETO modes in GaN and AlN layers were determined: for the mode E2H a (GaN) = -1027, b (GaN) = -597, a (AlN) = -1216, b (AlN) = -969; for the mod ETO a (GaN) = -1086, b (GaN) = -204, a (AlN) = -915, b (AlN) = -567. Product Description popup.authors Бєляєв Олександр Євгенович Кладько Василь Петрович Коломис Олександр Федорович Коротєєв Вадим В'ячеславович Кочелап Вячеслав Олександрович Кучук Андріан Володимирович Лящук Юрій Миколайович Наумов Андрій Вадимович Райчева Валентина Григорівна popup.nrat_date 2020-04-02 Close