Au-Au bond strengthening in photoexcited dimers of an Au(I) complex is captured in solution as oscillations of femtosecond absorption signals. The subsequent dynamics, when compared to the trimer's data, confirm that the bent-to-linear structural change of the trimer occurs in the first few picoseconds.

Nuclear magnetic resonance (NMR) spectrum of the short-lived nucleus 17 N (I = 1/2, T 1/2 = 4.17s) in liquid water was measured by means of the β-NMR technique to clarify the chemical species formed by nitrogen ions injected into water. We have improved the spectral resolution to 5ppm in the full width at half maximum which is about 1/40 times compared to the previous study. The shape of the obtained spectrum indicated that it may consist of multiple resonance lines rather than a single line. Some possibilities regarding the chemical states of nitrogen in water are discussed based on the present result. Keywords β-NMR • Nitrogen ion • H 2 O • Spin-spin coupling This article is part of the Topical Collection on

Sputter-deposited indium–tin oxide (ITO) electrodes became ohmic contacts for unintentionally doped β-Ga2O3(010) substrates with a carrier concentration of 2 × 1017 cm−3 after rapid thermal annealing in a wide range of annealing temperatures of 900–1150 °C. The formation of an ohmic contact is attributed to interdiffusion between ITO and β-Ga2O3, as evidenced by the results of transmission electron microscopy and energy-dispersive X-ray spectroscopy. The interdiffusion decreases the band gap and increases the donor concentration of β-Ga2O3 at the interface, and forms an intermediate semiconductor layer desirable for carrier transport. The ITO ohmic contact is particularly useful for future β-Ga2O3 devices operated at high temperatures.

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High-quality β-(AlxGa1−x)2O3 (x = 0–0.37) films were epitaxially grown on β-Ga2O3 (100) substrates by oxygen-radical-assisted pulsed-laser deposition with repeating alternate ablation of single crystals of β-Ga2O3 and α-Al2O3. The bandgap was tuned from 4.55 ± 0.01 eV (x = 0) to 5.20 ± 0.02 eV (x = 0.37), where bowing behavior was observed. The band alignment at the β-(AlxGa1−x)2O3/β-Ga2O3 interfaces was found to be type-I with conduction- and valence-band offsets of 0.52 ± 0.08 eV (0.37 ± 0.08 eV) and 0.13 ± 0.07 eV (0.02 ± 0.07 eV) for x = 0.37 (0.27), respectively. The large conduction-band offsets are ascribed to the dominant contribution of the cation-site substitution to the conduction band.