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Hexagonal boron nitride (h-BN) has become a popular material in solar-blind ultraviolet (SBUV) detection due to its ultra-wide bandgap, high optical absorption coefficient, high breakdown field strength and high thermal conductivity. However, the high deposition temperature restricts the choice of h-BN film substrates and hinders the fabrication of h-BN flexible devices. In this work, several h-BN films have been prepared by RF magnetron sputtering with B as the target at room temperature, and based on the films, SBUV detectors were also fabricated with the metal-semiconductor-metal (MSM) structure, which exhibit an extremely low dark current (0.07 pA) and a high response (1.37 μA/W) at 3 V. These results establish the feasibility of fabricating h-BN films and SBUV detectors at room temperature.

Yb3+ and Ho3+ co-doped Lu1.5Y1.5Al5O12 (abbr. as Yb/Ho:LuYAG) crystals were grown using Czochralski method, and their spectroscopic properties were systematically studied. The effect of the doping concentration of Yb3+ on the spectroscopic performances were discussed comprehensively, and it was found that the 1 at% Ho3+, 5 at% Yb3+:LuYAG crystal shows better spectral properties. For example, the sensitized ion Yb3+ can transfer 64.9 % of its own energy to Ho3+ to achieve effective pumping of Ho3+ and thus obtain the intense infrared emissions with peak at 2090 nm. Furthermore, under the pumping of 937 nm, the green, red and infrared waveband emissions with peaks at 558, 667 and 756 nm were observed in it, and the red emission is much stronger than the other two emissions. The results show that 1 at% Ho3+, 5 at% Yb3+:LuYAG crystals are excellent gain media for realizing up-converted visible lasers and infrared lasers in the ∼2.09 µm band.