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Of all publications in the section: 4
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Article
Gordeev N. Y., Максимов М. В., Payusov A. S. et al. Semiconductor Science and Technology. 2021. Vol. 36. No. 1.

We study material gain of a novel type of quantum heterostructures of mixed (0D/2D) dimensionality referred to as quantum well-dots (QWDs). To evaluate the material gain in a broad range of injection currents (30–1200 A cm−2 per-layer) we studied edge-emitting lasers with various numbers of InGaAs/GaAs QWD layers in the active region and different waveguide designs. The dependence of the material gain on the current is well fitted by an empirical exponential equation similar to the one used for quantum dots (QDs) in the whole range of injection current densities. The estimated QWD transparency current-density-per-layer of 31 A cm−2 ranks between the values reported for quantum wells and QDs. The maximal QWD material gain as high as 1.1·104 cm−1 has been measured. The results obtained confirm specific gain properties of InGaAs QWDs making them promising active media for lasers, superluminescence diodes and optical amplifiers.

Added: Mar 11, 2021
Article
Bondarenko G.G., Skazochkin A. V., Krutogolov Y. K. Semiconductor Science and Technology. 1996. Vol. 11. No. 4. P. 495-501.

The effects of varying the ammonia flux on the concentrations of background Si and free carriers and on deep traps for majority and minority carriers in n-GaP layers grown by vapour epitaxy have been studied  by secondary ion mass spectrometry and deep level transient spectroscopy. The contribution from the background silicon to the free carrier concentration in samples variously doped with nitrogen is discussed. It is shown that the deep centre at Ec  - 0.24 eV may be attributed to silicon. The model of this centre, in the form SiGa-Vp accounts for experimental results obtained in the present work and those already reported. The concentration of the dominant nonradiative recombination centre at EV + 0.75 eV is studied, depending on growth conditions, and its model is proposed in the form of a complex consisting of intrinsic defects.The effects of varying the ammonia flux on the concentrations of background Si and free carriers and on deep traps for majority and minority carriers in n-GaP layers grown by vapour epitaxy have been studied  by secondary ion mass spectrometry and deep level transient spectroscopy. The contribution from the background silicon to the free carrier concentration in samples variously doped with nitrogen is discussed. It is shown that the deep centre at Ec  - 0.24 eV may be attributed to silicon. The model of this centre, in the form SiGa-Vp accounts for experimental results obtained in the present work and those already reported. The concentration of the dominant nonradiative recombination centre at EV + 0.75 eV is studied, depending on growth conditions, and its model is proposed in the form of a complex consisting of intrinsic defects.

Added: Nov 15, 2013
Article
Tikhonov E., Shovkun D. V., Ercolani D. et al. Semiconductor Science and Technology. 2016. Vol. 31. No. 104001. P. 1-6.

We apply noise thermometry to characterize charge and thermoelectric transport in single InAs nanowires (NWs) at a bath temperature of 4.2 K. Shot noise measurements identify elastic diffusive transport in our NWs with negligible electron–phonon interaction. This enables us to set up a measurement of the diffusion thermopower. Unlike previous approaches, we make use of a primary electronic noise thermometry to calibrate a thermal bias across the NW. In particular, this enables us to apply a contact heating scheme, which is much more efficient in creating the thermal bias as compared to conventional substrate heating. The measured thermoelectric Seebeck coefficient exhibits strong mesoscopic fluctuations in dependence on the back-gate voltage that is used to tune the NW carrier density. We analyze the transport and thermoelectric data in terms of an approximate Mott's thermopower relation and evaluate a gate-voltage to the Fermi energy conversion factor.

Added: Feb 1, 2019
Article
Koshelev O., Nechaev D., Brunkov P. et al. Semiconductor Science and Technology. 2021. Vol. 36. No. 3.

Stress evolution was studied in up to similar to 3 mu m thick AlN templates, comprising similar to 65 nm thick AlN nucleation layers (NLs) and thick buffer layers (BLs), grown using different growth modes and conditions by plasma-assisted molecular beam epitaxy (PA MBE) on c-Al2O3. Growth of both the NL and BL in a standard PA MBE mode at N-rich conditions (at flux ratio Al/N-2* similar to 0.5) led to instant generation of a relatively high tensile stress (similar to 1.5 GPa) which is maintained throughout the entire growth. On the contrary, NLs, grown using a migration-enhanced epitaxy (MEE), demonstrated a transition from the initial compressive stress to stress-free growth, which is usually observed in the Volmer-Weber films. Further growth of thick AlN BLs on the MEE-NLs at various Al/N-2* ratios revealed a wide variety of stress evolution processes. The BL growth by using metal-modulated epitaxy (MME) at Me-rich conditions with Al/N-2* similar to 1.33 led to a gradual decrease in the initial compressive stress in the 2D AlN layers, whereas standard PA MBE growth of 3D BL at N-rich conditions (Al/N-2* similar to 0.92) exhibited a fast transition from the initial compressive stress to tensile stress. Moreover, we succeeded in achieving the quasi-stress-free growth of a 3.1 mu m thick AlN BL using the MME growth mode at the optimum flux ratio Al/N-2* = 1.05. These results were compared with the results of other authors and explained using a kinetic approach to description of stress evolution during PA MBE of AlN/c-Al2O3 templates, taking into account several simultaneously acting competitive mechanisms of continuous generation of tensile and compressive stresses.

Added: May 31, 2021