The fabrication of low-resistance and thermal stable ohmic contacts is important for realization of reliable SiC devices. For then-type SiC, Ni-based metallization is most commonly used for Schottky and ohmic contacts. Many experimental studies have been performed in order to understand the mechanism of ohmic contact formation and different models were proposed to explain the Schottky to ohmic transition for Ni/SiC contacts. In the present review, we summarize the last key results on the matter and post open questions concerning the unclear issues of ohmic contacts ton-type SiC. Analysis of the literature data and our own experimental observations have led to the conclusion that the annealing at high temperature leads to the preferential orientation of silicide at the heterointerface (0001)SiC//(013)δ-Ni2Si. Moreover, we may conclude that onlyδ-Ni2Si grains play a key role in determining electrical transport properties at the contact/SiC interface. Finally, we show that the diffusion barriers with free diffusion path microstructure can improve thermal stability of metal-SiC ohmic contacts for high-temperature electronics.

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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.

The recent rapid development of transparent electronics, notably displays and control circuits, requires the development of highly transparent energy storage devices, such as supercapacitors. The devices reported to date utilize carbon-based electrodes for high performance, however at the cost of their low transparency around 50%, insufficient for real transparent devices. To overcome this obstacle, in this communication highly transparent supercapacitors were fabricated based on ZnO/MnO nanostructured electrodes. ZnO served as an intrinsically transparent skeleton for increasing the electrode surface, while MnO nanoparticles were applied for high capacitance. Two MnO synthesis routes were followed, based on the reaction of KMnO with Mn(Ac) and PAH, leading to the synthesis of β-MnO with minority α-MnO nanoparticles and amorphous MnO with embedded β-MnO, respectively. The devices based on such electrodes showed high capacitances of 2.6 mF cm and 1.6 mF cm, respectively, at a scan rate of 1 mV s and capacitances of 104 μF cm and 204 μF cm at a very high rate of 1 V s, not studied for transparent supercapacitors previously. Additionally, the Mn(Ac) devices exhibited very high transparencies of 86% vs. air, far superior to other transparent energy storage devices reported with similar charge storage properties. This high device performance was achieved with a non-acidic LiCl gel electrolyte, reducing corrosion and handling risks associated with conventional highly concentrated acidic electrolytes, enabling applications in safe, wearable, transparent devices.

In the paper, the results of technological investigations on planar optical waveguides based on high band gap oxide semiconductors were presented. Investigations concerned the technologies of depositing very thin layers of: zinc oxide ZnO, titanium dioxide TiO2 and tin dioxide SnO2 on substrates of quartz glass plates. There were investigated both morphological structures of the produced layers and their optical properties. The paper also presents investigations on the technology of input-output light systems in the Bragg grating structures.