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Near-ultraviolet 400-nm InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with and without an in situ rough SiNx interlayer inserted into the n-GaN underlying layer were grown on c-face sapphire substrates by metalorganic vapor phase epitaxy. Inserting the SiNx interlayer into the n-GaN underlying layer slightly reduced leakage current induced by reducing the defect density. Additionally, an enhancement of light extraction for the LED with a SiNx interlayer is expected because of the increased intensity of light scattered on the SiNx nanomask, changing the directions of propagation of light. Consequently, the emission efficiency of an LED with an in situ rough SiNx interlayer doubles that without a SiNx interlayer.

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In situ growth of Ba1−xKxBiO3 (BKBO) films by laser ablation has been studied as a function of gas pressure and substrate temperature in O2, N2O, and N2O/O2 (1:1), respectively. The superconducting BKBO films can be grown at 410–500 °C in 15–60 mTorr of O2, at 390–510 °C in 20–2000 mTorr of N2O, and at 390–500 °C in 15–700 mTorr of N2O/O2 (1:1), respectively. Oxygen partial pressure plays an important role in controlling the doping of potassium into the BKBO phase during in situ deposition and hence the growth of the superconducting films. The optimum deposition pressures are 40 mTorr of O2, 30–50 mTorr of N2O, and 20–50 mTorr of N2O/O2 (1:1), under which not only the temperature range available for growing the superconducting films is wider but also the Tc’s of the as-grown films are higher. N2O used as an oxidation gas during growth is efficient in suppressing the crack formation in the BKBO films on cooling. The target composition also plays an important role in film growth. The optimal target composition studied is Ba:K:Bi=0.6:0.8:1.0.

This study develops a highly transparent nickel-oxide (NiO )-indium-tin-oxide (ITO) transparent Ohmic contact with excellent current spreading for -GaN to increase the optical output power of nitride-based light-emitting diodes (LEDs). The NiO -ITO transparent Ohmic contact layer was prepared by electron beam in-situ evaporation without postdeposition annealing. Notably, the transmittance of the NiO -ITO exceeds 90% throughout the visible region of the spectrum and approaches 98% at 470 nm. Moreover, GaN LED chips with dimensions of 300 300 m fabricated with the NiO -ITO transparent Ohmic contact were developed and produced a low forward voltage of 3.4 V under a nominal forward current of 20 mA and a high optical output power of 6.6 mW. The experimental results indicate that NiO -ITO bilayer Ohmic contact with excellent current spreading and high transparency is suitable for fabricating high-brightness GaN-based light-emitting devices.