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In this study, the structural and electrical properties of orthorhombic κ-Ga2O3 films prepared using Halide Vapor Phase Epitaxy (HVPE) on AlN/Si and GaN/sapphire templates were studied. For κ-Ga2O3/AlN/Si structures, the formation of two-dimensional hole layers in the Ga2O3 was studied and, based on theoretical calculations, was explained by the impact of the difference in the spontaneous polarizations of κ-Ga2O3 and AlN. Structural studies indicated that in the thickest κ-Ga2O3/GaN/sapphire layer used, the formation of rotational nanodomains was suppressed. For thick (23 μm and 86 μm) κ-Ga2O3 films grown on GaN/sapphire, the good rectifying characteristics of Ni Schottky diodes were observed. In addition, deep trap spectra and electron beam-induced current measurements were performed for the first time in this polytype. These experiments show that the uppermost 2 µm layer of the grown films contains a high density of rather deep electron traps near Ec − 0.3 eV and Ec − 0.7 eV, whose presence results in the relatively high series resistance of the structures. The diffusion length of the excess charge carriers was measured for the first time in κ-Ga2O3. The film with the greatest thickness of 86 μm was irradiated with protons and the carrier removal rate was about 10 cm−1, which is considerably lower than that for β-Ga2O3.

In this study, the results of hydrogen plasma treatments of β-Ga2O3, α-Ga2O3, κ-Ga2O3 and γ-Ga2O3 polymorphs are analyzed. For all polymorphs, the results strongly suggest an interplay between donor-like hydrogen configurations and acceptor complexes formed by hydrogen with gallium vacancies. A strong anisotropy of hydrogen plasma effects in the most thermodynamically stable β-Ga2O3 are explained by its low-symmetry monoclinic crystal structure. For the metastable, α-, κ- and γ-polymorphs, it is shown that the net result of hydrogenation is often a strong increase in the density of centers supplying electrons in the near-surface regions. These centers are responsible for prominent, persistent photocapacitance and photocurrent effects.

In this study, the results of hydrogen plasma treatments of β-Ga[sub.2]O[sub.3], α-Ga[sub.2]O[sub.3], κ-Ga[sub.2]O[sub.3] and γ-Ga[sub.2]O[sub.3] polymorphs are analyzed. For all polymorphs, the results strongly suggest an interplay between donor-like hydrogen configurations and acceptor complexes formed by hydrogen with gallium vacancies. A strong anisotropy of hydrogen plasma effects in the most thermodynamically stable β-Ga[sub.2]O[sub.3] are explained by its low-symmetry monoclinic crystal structure. For the metastable, α-, κ- and γ-polymorphs, it is shown that the net result of hydrogenation is often a strong increase in the density of centers supplying electrons in the near-surface regions. These centers are responsible for prominent, persistent photocapacitance and photocurrent effects.

In this study, the structural and electrical properties of orthorhombic κ-Ga O films prepared using Halide Vapor Phase Epitaxy (HVPE) on AlN/Si and GaN/sapphire templates were studied. For κ-Ga O /AlN/Si structures, the formation of two-dimensional hole layers in the Ga O was studied and, based on theoretical calculations, was explained by the impact of the difference in the spontaneous polarizations of κ-Ga O and AlN. Structural studies indicated that in the thickest κ-Ga O /GaN/sapphire layer used, the formation of rotational nanodomains was suppressed. For thick (23 μm and 86 μm) κ-Ga O films grown on GaN/sapphire, the good rectifying characteristics of Ni Schottky diodes were observed. In addition, deep trap spectra and electron beam-induced current measurements were performed for the first time in this polytype. These experiments show that the uppermost 2 µm layer of the grown films contains a high density of rather deep electron traps near E - 0.3 eV and E - 0.7 eV, whose presence results in the relatively high series resistance of the structures. The diffusion length of the excess charge carriers was measured for the first time in κ-Ga O . The film with the greatest thickness of 86 μm was irradiated with protons and the carrier removal rate was about 10 cm , which is considerably lower than that for β-Ga O .

In this study, the structural and electrical properties of orthorhombic κ-Ga[sub.2]O[sub.3] films prepared using Halide Vapor Phase Epitaxy (HVPE) on AlN/Si and GaN/sapphire templates were studied. For κ-Ga[sub.2]O[sub.3]/AlN/Si structures, the formation of two-dimensional hole layers in the Ga[sub.2]O[sub.3] was studied and, based on theoretical calculations, was explained by the impact of the difference in the spontaneous polarizations of κ-Ga[sub.2]O[sub.3] and AlN. Structural studies indicated that in the thickest κ-Ga[sub.2]O[sub.3]/GaN/sapphire layer used, the formation of rotational nanodomains was suppressed. For thick (23 μm and 86 μm) κ-Ga[sub.2]O[sub.3] films grown on GaN/sapphire, the good rectifying characteristics of Ni Schottky diodes were observed. In addition, deep trap spectra and electron beam-induced current measurements were performed for the first time in this polytype. These experiments show that the uppermost 2 µm layer of the grown films contains a high density of rather deep electron traps near E[sub.c] − 0.3 eV and E[sub.c] − 0.7 eV, whose presence results in the relatively high series resistance of the structures. The diffusion length of the excess charge carriers was measured for the first time in κ-Ga[sub.2]O[sub.3]. The film with the greatest thickness of 86 μm was irradiated with protons and the carrier removal rate was about 10 cm[sup.−1], which is considerably lower than that for β-Ga[sub.2]O[sub.3].

Subject of Research.The paper deals with processes of formation and transformation of defects during multi-stage growth of thick gallium nitride layers with hydride vapor phase epitaxy on GaN/Al2O3 substrates with buried column pattern formed with the use of metal-organic vapor phase epitaxy. Methods. The growth of initial GaN layers was performed with the use of metal-organic vapor phase epitaxy. On the surface of the initial layers columns with the height of 800 nm were generated by means of ion etching. These columns were overgrown with 3-4 µm-thick GaN layers. On thus formed substrate multi-stage growth of GaN layers was performed with the use of hydride vapor-phase epitaxy. The total thickness of GaN layers was 100-1500 µm. The grown layers were studied by optical and electron microscopy and Raman spectroscopy. Main Results. Density of threading dislocations in the layers grown by hydride vapor-phase epitaxy was (3-6)·107 cm-2, that was one order of magnitude lower than in the used substrate, and two to three orders lower than dislocation density in typical GaN layers grown on commercial sapphire substrates. Raman spectroscopy data were indicative of low level of mechanical stress in the layers and their high structural uniformity. It was established that under multi-stage growth conditions, non-catastrophic cracks (those that do not cause sample destruction) are able to transform into macropores and appear to be an important structural element, serving to stress relaxation in the bulk of thick gallium nitride layers grown on foreign substrates. Practical Relevance. The results of the study can be used in the development of III-nitride heterostructures for optoelectronics and high-power and high-frequency microelectronics.

The paper presents the results of gas dynamic calculation and strength analysis required to optimize the mathematical model of the body of the catalytic collector of a passenger car. Based on the obtained results of numerical modeling, the optimization of the case was performed. As a result of the gas-dynamic calculation, the optimal variant of the catalytic collector housing with the required uniformity of the exhaust gas flow in the input section of the catalyst (coefficient of unevenness (UI > 0.8)) was selected. According to the results of the strength analysis, stainless steel was selected to withstand emerging mechanical stresses at maximum temperatures up to 600 °C.

In this article, we investigate the development and use of thermal memory elements based on thin-film aluminum devices on silicon wafer. To stabilize their operation and reduce the number of errors during the read/write process of thermal information in such devices, we propose an algorithm (referred to as the floating zero algorithm) for adjusting the temperature conditions of thermal memory cells. This algorithm controls the thermal memory cells on silicon under varying ambient temperature conditions. We tested the algorithm performance using an experimental thermal memory sample at room temperature. Additionally, we conducted a study on the degradation process of the sample under high electrothermal loading conditions. The results showed that the degradation process in the sample starts when a single current pulse of duration τ i  ≥ 100 µs and amplitude density j i ≥ 8.5 × 10 10 A/m 2 ) flows through the device. We propose a criterion for determining the safe operation area γ of the device under investigation and experimentally determine its value γ  = 6.0( VA √ s ).

Sergey Nikolaev, Stylianos Antonarakis and colleagues analyze the genetic architecture of 293 basal cell carcinomas (BCCs) and characterize their mutational landscape. They observe UV signature mutations and identify new driver mutations in MYCN , PTPN14 and LATS1 in BCC. Basal cell carcinoma (BCC) of the skin is the most common malignant neoplasm in humans. BCC is primarily driven by the Sonic Hedgehog (Hh) pathway. However, its phenotypic variation remains unexplained. Our genetic profiling of 293 BCCs found the highest mutation rate in cancer (65 mutations/Mb). Eighty-five percent of the BCCs harbored mutations in Hh pathway genes ( PTCH1 , 73% or SMO , 20% ( P = 6.6 × 10 −8 ) and SUFU , 8%) and in TP53 (61%). However, 85% of the BCCs also harbored additional driver mutations in other cancer-related genes. We observed recurrent mutations in MYCN (30%), PPP6C (15%), STK19 (10%), LATS1 (8%), ERBB2 (4%), PIK3CA (2%), and NRAS , KRAS or HRAS (2%), and loss-of-function and deleterious missense mutations were present in PTPN14 (23%), RB1 (8%) and FBXW7 (5%). Consistent with the mutational profiles, N-Myc and Hippo-YAP pathway target genes were upregulated. Functional analysis of the mutations in MYCN , PTPN14 and LATS1 suggested their potential relevance in BCC tumorigenesis.

The aim of this study was to assess the prognostic value of different nutritional screening tools in patients undergoing cardiopulmonary bypass with regard to an adverse clinical course. This prospective cohort study analyzed 894 adult patients who underwent cardiopulmonary bypass. Patients were screened using four nutritional screening tools: Nutritional Risk Screening 2002 (NRS-2002), the Malnutrition Universal Screening Tool (MUST), the Mini-Nutritional Assessment (MNA), and the Short Nutritional Assessment Questionnaire (SNAQ). Nutritional status was assessed using the Subjective Global Assessment. In-hospital mortality, postoperative complications, length of stay in the intensive care unit, and length of hospitalization were analyzed. The sensitivities of the SNAQ, MUST, and NRS-2002 to detect the malnutrition confirmed by the Subjective Global Assessment were 91.5%, 97.9%, and 38.3%, respectively, and the MNA showed a sensitivity of 81.8% for the elderly. Malnutrition detected by the SNAQ, MUST, and NRS-2002 was associated with postoperative complications (odds ratios [ORs] 1.75, 1.98, and 1.82, respectively) and a stay in the intensive care unit longer than 2 d (ORs 1.46, 1.56, and 2.8). Malnutrition as detected by the SNAQ and MUST was also associated with prolonged hospitalization (ORs 1.49 and 1.59). According to multivariate logistic regression analysis, postoperative complications were independently predicted by the European System for Cardiac Operative Risk Evaluation (OR 1.1, P < 0.0001), cardiopulmonary bypass time (OR 1.01, P < 0.0001), and malnutrition identified by the MUST (OR 1.2, P = 0.01). The MUST independently predicts postoperative complications. The SNAQ and MUST have comparable accuracy in detecting malnutrition. Whether preoperative nutritional therapy would improve the outcome in malnourished patients needs to be studied.