We demonstrate high output power UVC-LEDs from 230 to 237 nm on AlN single-crystal substrates. The UVC-LEDs show a single peak in the electroluminescence spectrum, from 20 to 300 mA. Forward voltages were typically ∼7 V at 100 mA while measured initial output powers at 237 nm, 235 nm, 233 nm and 230 nm were 2.2 mW, 1.9 mW, 1.5 mW and 1.2 mW, respectively. At 20 mA, the measured wall-plug efficiencies were 0.37%, 0.32%, 0.25% and 0.19% at the same wavelengths, respectively. These devices have demonstrated over 3600 h of lifetime operating at 20 mA.

An Al0.6Ga0.4N/Al0.5Ga0.5N metal–semiconductor–metal (MSM) deep-ultraviolet (DUV) photodetector was developed. It possesses both high photosensitivity and high rejection ratios in comparison to photomultiplier tubes (PMTs). The photodetector was designed to have a two-dimensional electron gas layer at the Al0.6Ga0.4N/Al0.5Ga0.5N hetero-interface, which plays an important role in increasing the photosensitivity. Additionally, for reducing the dark current, a V/Al/Mo/Au electrode was employed as a Schottky electrode with an appropriate barrier height. Upon irradiation with 10 μW/cm2, an extremely low dark current (10−11 A) and high photocurrent (5 × 10−5 A) were achieved at a bias voltage of 5 V. The photodetector was true solar-blind with a cut-off wavelength of 280 nm. A high photosensitivity of 106 A/W and a rejection ratio of 106 were realized under the irradiation of 10 nW/cm2 DUV photons. The present results revealed that the AlGaN/AlGaN MSM DUV photodetector is one of the most suitable candidates for an all solid-state photodetector with a performance superior to PMTs.

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A novel microchip-sized InSb photodiode infrared sensor (InSb PDS) operating at room temperature is reported. There is no power consumption on the InSb PDS itself, since it works in photovoltaic mode to output an open-circuit voltage. The InSb PDS has a typical responsivity of 1,900 V/W and an output noise of 0.15 µV/Hz 1/2 . A detectivity (D * ) of 2.8x10 8 cmHz 1/2 /W has been obtained at 300 K. The InSb PDS is finally molded with plastic on a Quad Flat Non-leaded (QFN) package, having performance high enough for applications such as mobile electronic equipments, personal computers and consumer electronics.