Lasing oscillation from a GaAs1-xBix/GaAs semiconductor chip with a Fabry–Perot cavity is acheived for the first time by photo-pumping. The GaAs0.975Bi0.025 active layer was grown at a very low temperature of 350 °C by molecular beam epitaxy. The characteristic temperature of the laser was 83 K between 150 and 240 K. The lasing emission peak energy decreased at a constant rate of -0.18 meV/K, which is only 40% of the temperature coefficient of the GaAs band gap in this temperature range. Above 240 K, the lasing threshold pumping power increased sharply, and the lasing emission peak energy started shifting to a shorter wavelength.

Anisotropic lattice relaxation in non-c-plane InGaN/GaN multiple quantum wells J. Appl. Phys. 112, 033513 (2012) Influence of laser lift-off on optical and structural properties of InGaN/GaN vertical blue light emitting diodes AIP Advances 2, 022122 (2012) Vertical nonpolar growth templates for light emitting diodes formed with GaN nanosheets Appl. Phys. Lett. 100, 033119 (2012) Irregular spectral position of E || c component of polarized photoluminescence from m-plane InGaN/GaN multiple quantum wells grown on LiAlO2 Appl. Phys. Lett. 99, 232114 (2011) Improvement in spontaneous emission rates for InGaN quantum wells on ternary InGaN substrate for lightemitting diodes

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For hydrogen sensor and storage applications, films of Au and Pd were (i) cosputtered at different rates or (ii) deposited in a sequential layer-by-layer fashion on a cover glass. Peculiarities of hydrogen uptake and release were optically monitored using 1.3 µm wavelength light. Increase of optical transmission was observed for hydrogenated Pd-rich films of 10-30 nm thickness. Up to a three times slower hydrogen release took place as compared with the hydrogen uptake. Compositional ratio of Au:Pd and thermal treatment of films provided control over the optical extinction changes and hydrogen uptake/release time constants. Higher uptake and release rates were observed in the annealed Au:Pd films as compared to those deposited at room temperature and were faster for the Au-richer films. Three main parameters relevant for sensors: sensitivity, selectivity, stability (reproducibility) are discussed together with the hydrogenation mechanism in Au:Pd alloys.

Deep-level transient spectroscopy measurements reveal deep-hole traps with activation energies of 0.43 and 0.23 eV in p-type GaAs1-x Bi x samples with x = 1.2 and 3.4%, respectively, grown at 370 °C by molecular beam epitaxy. In spite of low-temperature growth, the deep-level trap concentration is suppressed on the order of 1015 cm-3, suggesting that Bi atoms contribute to the enhancement of migration to prevent the formation of point defects. The possible origin of the hole traps is discussed in connection with arsenic antisite, AsGa, and bismuth antisite, BiGa.