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Effects of aluminum (Al) and nitrogen (N) implantation performed at room and at elevated (500 °C) temperatures on epitaxial n-type 4H polytype silicon carbide as well as post-implantation annealing have been studied by Raman scattering spectroscopy. The amorphization of 4H–SiC is observed because of ion implantation effects. The Raman analysis showed that the recovery of the crystallinity increased with an increase in the annealing temperature. However, for samples implanted with high doses, the full crystal recovery was not complete even with annealing temperatures up to 1800 °C, and crystal defects were still present in the recrystallized layer, which was confirmed by transmission electron microscopy. Raman scattering spectra were collected at room temperature using a micro-Raman spectrometer. The visible (488 nm) and deep ultraviolet (266 nm) lasers were used as excitation sources. For the DUV laser, the optical penetration depth is less than the implanted layer thickness, and the area near the surface layer can be exactly probed. In contrast, the visible Raman spectrum shows bands characteristic of bulk 4H–SiC, which arise from the underlying non-implanted region. Based on the analysis of the longitudinal optical phonon–plasmon coupled mode, the electrical parameters for N2+ implanted samples were evaluated, where electron concentration n = 3.05 × 1018 cm−3 and mobility μ = 50 cm2/V s, respectively. The results are consistent with the parameters measured by the Hall method.

The focused ion beam (FIB) technique was used to fabricate a nanothermocouple (with a 90 nm wide nanojunction) based on a metal–semiconductor (Pt–Si) structure, which showed a sensitivity up to 10 times larger (with Seebeck coefficient up to 140 µV/K) than typical metal–metal nanothermocouples. In contrast to the fabrication of nanothermocouples which requires a high-tech semiconductor manufacturing line with sophisticated fabrication techniques, environment, and advanced equipment, FIB systems are available in many research laboratories without the need for a high-tech environment, and the described processing is performed relatively quickly by a single operator. The linear response of the manufactured nanothermocouple enabled sensitive measurements even with small changes of temperature when heated with a stream of hot air. A nonlinear response of the nanothermocouple (up to 83.85 mV) was observed during the exposition to an argon-laser beam with a high optical power density (up to 17.4 Wcm−2), which was also used for the laser annealing of metal–semiconductor interfaces. The analysis of the results implies the application of such nanothermocouples, especially for the characterization of laser beams with nanometer spatial resolution. Improvements of the FIB processing should lead to an even higher Seebeck coefficient of the nanothermocouples; e.g., in case of the availability of other suitable metal sources (e.g., Cr).

In this paper, the study of defects in InAs/GaSb type-II superlattices using high-resolution an x-ray diffraction method as well as scanning (SEM) and transmission (TEM) electron microscopy is presented. The investigated superlattices had 200 (#SL200), 300 (#SL300), and 400 (#SL400) periods and were grown using molecular beam epitaxy. The growth conditions differed only in growth temperature, which was 370 °C for #SL400 and #SL200, and 390 °C for #SL300. A wings-like diffuse scattering was observed in reciprocal space maps of symmetrical (004) GaSb reflection. The micrometer-sized defect conglomerates comprised of stacking faults, and linear dislocations were revealed by the analysis of diffuse scattering intensity in combination with SEM and TEM imaging. The following defect-related parameters were obtained: (1) integrated diffuse scattering intensity of 0.1480 for #SL400, 0.1208 for #SL300, and 0.0882 for #SL200; (2) defect size: (2.5–3) μm × (2.5–3) μm –#SL400 and #SL200, (3.2–3.4) μm × (3.7–3.9) μm –#SL300; (3) defect diameter: ~1.84 μm –#SL400, ~2.45 μm –#SL300 and ~2.01 μm –#SL200; (4) defect density: 1.42 × 106 cm−2 –#SL400, 1.01 × 106 cm−2 –#SL300, 0.51 × 106 cm−2 –#SL200; (5) diameter of stacking faults: 0.14 μm and 0.13 μm for #SL400 and #SL200, 0.30 μm for #SL300.

AlGaN/GaN high electron mobility transistors on semi-insulating bulk ammonothermal GaN have been investigated. By application of regrown ohmic contacts, the problem with obtaining low resistance ohmic contacts to low-dislocation high electron mobility transistor (HEMT) structures was solved. The maximum output current was about 1 A/mm and contact resistances was in the range of 0.3⁻0.6 Ω ·mm. Good microwave performance was obtained due to the absence of parasitic elements such as high access resistance.

With the development of novel device applications, e.g. in the field of robust and recyclable paper electronics, came an increased demand for the understanding and control of IGZO Schottky contact properties. In this work, a fabrication and characterization of flexible Ru–Si–O/IGZO Schottky barriers on paper is presented. It is found that an oxygen-rich atomic composition and microstructure of Ru–Si–O containing randomly oriented Ru inclusions with diameter of 3–5 nm embedded in an amorphous SiO2 matrix are effective in preventing interfacial reactions in the contact region, allowing to avoid pre-treatment of the semiconductor surface and fabricate reliable diodes at room temperature characterized by Schottky barrier height and ideality factor equal 0.79 eV and 2.13, respectively. [ABSTRACT FROM AUTHOR]