Thermal atomic layer-deposited (ALD) aluminum oxide (Al₂O₃) acquires high negative fixed charge density (Q _f) and sufficiently low interface trap density after annealing, which enables excellent surface passivation for crystalline silicon. Q _f can be controlled by varying the annealing temperatures. In this study, the effect of the annealing temperature of thermal ALD Al₂O₃ films on p-type Czochralski silicon wafers was investigated. Corona charging measurements revealed that the Q _f obtained at 300°C did not significantly affect passivation. The interface-trapping density markedly increased at high annealing temperature (>600°C) and degraded the surface passivation even at a high Q _f. Negatively charged or neutral vacancies were found in the samples annealed at 300°C, 500°C, and 750°C using positron annihilation techniques. The Al defect density in the bulk film and the vacancy density near the SiO _x /Si interface region decreased with increased temperature. Measurement results of Q _f proved that the Al vacancy of the bulk film may not be related to Q _f. The defect density in the SiO _x region affected the chemical passivation, but other factors may dominantly influence chemical passivation at 750°C.

We present the analysis of the brightest flare that was recorded in the Insight-HMXT data set in a broad energy range (2–200 keV) from the microquasar GRS 1915+105 during an unusual low-luminosity state. This flare was detected by Insight-HXMT among a series of flares during 2019 June 2 UTC 16:37:06–20:11:36 with a 2–200 keV luminosity of 3.4–7.27 × 10³⁸ erg s⁻¹. Basing on the broadband spectral analysis, we find that the flare spectrum shows different behaviors during bright and faint epochs. The spectrum of the flare can be fitted with a model dominated by a power-law component. Additional components show up in the bright epoch with a hard tail and in the faint epoch with an absorption line of ∼6.78 keV. The reflection component of the latter is consistent with an inner disk radius ∼five times larger than that of the former. These results on the giant flare during the “unusual” low-luminosity state of GRS 1915+105 may suggest that the source experiences a possible fast transition from a jet-dominated state to a wind-dominated state. We speculate that the evolving accretion disk and the large-scale magnetic field may play important roles in this peculiar huge flare.

A multi-responsiveness supramolecular metal-organic gel (MOG) has been prepared by using silver (I) nitrate and a simple ligand (L17) based on a biscarboxyl-functionalised benzimidazole derivative. The MOG that displays the formation of well-developed nanofibrillar networks composed of intertwined fibres was characterised by using field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (XRD) techniques. The FT-IR spectra and XRD show that supramolecular MOG was formed through an effective coordination of the ligand and Ag⁺. This MOG reveals outstanding reversible sol–gel transitions induced by changes of temperature and pH, as well as by addition of NH₄OH, ethylene diamine tetraacetic acid and Na₂S. In addition, the MOG also shows a good ability in dye sorption. These results demonstrate that this multichannel responsive smart MOG has the potential to be widely applied in materials science.