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[Display omitted] • The reliability of DLTS simulation is confirmed by the nonlocal hybrid functional. • The electron–phonon coupling is included to describe the hot carrier nonradiative capture in the DLTS simulation. • The DLTS simulation is verified by the radiation experiments. Deep level transient spectroscopy (DLTS) is a crucial technique to characterize the defects in semiconductor devices. Within the framework of the state-of-the-art density functional theory (DFT), the simulation for experimental DLTS spectra is realized successfully with high accuracy and intrinsic physics in this work, of which the reliability is confirmed by nonlocal hybrid functional. The electron–phonon coupling is included to describe the thermal-activated behavior of the hot carrier nonradiative capture reflected by DLTS signal. In the case study, the divacancy in silicon is employed for the flow of DLTS calculation as a benchmark, of which the results are verified by our 40 MeV Si irradiation experiments on the NPN and PNP bipolar junction transistors and previous reports. The problem we can address is the identification of defect characterized in DLTS experiments. The realization of DLTS simulation would have a profound significance for understanding the underlying physics in experimental observations and be a powerful leverage to define defect nature in semiconductors. [ABSTRACT FROM AUTHOR]

The evolution of ionizing radiation-induced defects in gated lateral p-n-p (GLPNP) bipolar transistors at different temperatures is investigated. The experimental results show that when the irradiation dose is less than 25 krad, the change in the reciprocal current gain (Δ (1/β)) increases by increasing the temperature gradually at a given dose. When the dose is more than 25 krad, Δ(1/β) increases first and then decreases at 200 °C by increasing the temperature at a given dose. Gate sweep (GS) technique and deep-level transient spectroscopy (DLTS) analyses show that the positive oxide trapped charges decrease by increasing the temperatures. When the temperature is less than 200 °C, the number of the interface traps gradually increases by increasing the temperature, but when the temperature increases to 200 °C, the number of the interface traps decreases. It indicates that the formation of the positive oxide trapped charges was inhibited at different temperatures above room temperature, and the formation of the interface traps was promoted at less than 200 °C and annealed significantly at 200 °C. Moreover, the change in the number of the interface traps in the transistors induced by the irradiation under different temperatures decides the degradation of the current gain. [ABSTRACT FROM AUTHOR]

Characteristics of displacement defects in the 3CK3637 PNP bipolar junction transistors (BJTs) irradiated by 10 MeV Si, 40 MeV Si and 25 MeV C ions are investigated in this paper. Electrical parameters are measured in-situ using KEITHLEY a 4200-SCS semiconductor characterization system during irradiations. The radiation-induced defects caused by various ions for different displacement damage doses are characterized by deep level transient spectroscopy (DLTS). Experimental results show that the electrical degradation increases with increasing irradiation fluence. It is worth noting that the increase trend of the electrical degradation is different for the three types of ions. For the 10 MeV Si ions, the electrical degradation linearly increases, while, for the 40 MeV Si and 25 MeV C ions, the electrical degradation increases nonlinearly. The change in the reciprocal of current gain (Δ(1/β)) caused by 40 MeV Si and 25 MeV C ions can be normalized in one line at lower displacement damage doses. As the displacement damage dose increases to a certain threshold, the Δ(1/β) deviates from the normalized line. Based on the DLTS analyses, the dominant displacement defects in the 3CK3637 PNP BJTs irradiated by 40 MeV Si and 25 MeV C ions change with increasing displacement dose, leading to the existence of threshold in the electrical degradation curve. [ABSTRACT FROM AUTHOR]

Wide bandgap β-Ga2O3 is an ideal candidate material with broad application prospects for power electronic components in the future. Aiming at the application requirements of β-Ga2O3 in space photoelectric devices, this work studies the influence of 40 MeV Si ion irradiation on the microstructure and optical properties of β-Ga2O3 epi-wafers. Raman spectroscopy analysis confirms that Si ion irradiation destroys the symmetric stretching mode of tetrahedral–octahedral chains in β-Ga2O3 epi-wafers, and the obtained experimental evidence of irradiation leads to the enhanced defect density of VO and VGa–VO from x-ray photoelectron spectroscopy. Combined with first-principles calculations, we conclude that most configurations of VO and VGa–VO are likely non-radiative, leading to quenching of experimental photoluminescence intensity. Unraveling optical degradation mechanism and predicting the optical application of β-Ga2O3 devices in the space environment by combining ground irradiation experiments with first-principles calculations still be one of the focuses of research in the future. [ABSTRACT FROM AUTHOR]

With the development of minimally invasive orthopedics, injectable materials for bone repair are attracted more attention, especially for those wound with a small external mouth and sizeable internal cavity. In this work, the hydrogel with features of thermo-responsiveness, degradability and injectability was designed and fabricated. The hydrogel, named as FHCS, is composed of Pluronic F-127 (F127) loaded with carboxymethyl chitosan/sodium alginate nanoparticles (nCS) and nanohydroxyapatite (nHA). The hydrogel FHCS was non-toxic and good hemocompatible. It can enhance the ALP activity and extracellular matrix calcification of MC3T3-E1 due to the chitosan-based nanoparticle components (nCS). Moreover, FHCS-5 (containing 5 mg/mL nCS) showed relative high expression of osteogenic genes and protein markers. Osteal regeneration was observed treated by FHCS-5 hydrogel in a critical-size rat calvarial bone defect model. CT scanning showed that the whole defect was basically covered by new bone after FHCS-5 hydrogel. The results of H&E staining and Masson's trichrome staining on histological sections further confirmed that FHCS-5 hydrogel promoted new osteal formation and maturation, which up regulated the osteogenic related genes and proteins of ALP, OCN, OPN through BMP/Smad signaling pathway. Hence, this study suggests that FHCS-5 hydrogels have a promising application for non-loading bone regeneration. [Display omitted] [ABSTRACT FROM AUTHOR]

Self-healing coatings have shown promise in controlling the degradation of scaffolds and addressing coating detachment issues. However, developing a self-healing coating for magnesium (Mg) possessing multiple biological functions in infectious environments remains a significant challenge. In this study, a self-healing coating was developed for magnesium scaffolds using oxidized dextran (OD), 3-aminopropyltriethoxysilane (APTES), and nano-hydroxyapatite (nHA) doped micro-arc oxidation (MHA), named OD-MHA/Mg. The results demonstrated that the OD-MHA coating effectively addresses coating detachment issues and controls the degradation of Mg in an infectious environment through self-healing mechanisms. Furthermore, the OD-MHA/Mg scaffold exhibits antibacterial, antioxidant, and anti-apoptotic properties, it also promotes bone repair by upregulating the expression of osteogenesis genes and proteins. The findings of this study indicate that the OD-MHA coated Mg scaffold possessing multiple biological functions presents a promising approach for addressing infectious bone defects. Additionally, the study showcases the potential of polysaccharides with multiple biological functions in facilitating tissue healing even in challenging environments. [Display omitted] [ABSTRACT FROM AUTHOR]

The electrical degradation in AlGaN/GaN high-electron-mobility transistors (HEMTs) is examined under irradiation with 7.6-MeV carbon (C), 20-MeV oxygen (O), and 30-MeV fluorine (F) ions in situ. To characterize the radiation damage in the HEMTs, the ionizing dose Di, displacement dose Dd, and number of vacancies versus the chip depth in the devices have been calculated for heavy ions. As expected, in all three types of HEMTs, the output current decreases more than 30% and threshold voltage positive shifts after the irradiation fluence of 4 × 1012 ions/cm2. The performance degradation of AlGaN/GaN HEMTs is caused by radiation-induced charged defects. Based on calculation and experimental results, it is shown that the nonionizing energy loss (NIEL) method is not suitable for estimating the degradation of AlGaN/GaN HEMTs either considering gallium vacancy or considering both gallium vacancy and nitrogen vacancy. In the same displacement damage dose, the threshold voltage degradation rate depends on the type of incident particles and independent of the channel length. The damage caused by carbon ions is the smallest and the damage caused by fluoride ions is the largest. [ABSTRACT FROM AUTHOR]