System for Hydrogen Sensing

A low-power, wireless gas-sensing system is designed to safeguard the apparatus to which it is attached, as well as associated personnel. It also ensures the efficiency and operational integrity of the hydrogen-powered apparatus. This sensing system can be operated with lower power consumption (less than 30 nanowatts), but still has a fast response. The detecting signal can be wirelessly transmitted to remote locations, or can be posted on the Web. This system can also be operated by harvesting energy

Real-time monitoring of low-temperature hydrogen plasma passivation of GaAs

By monitoring photoluminescence (PL) in real time and in situ, hydrogen plasma operating conditions have been optimized for surface passivation of native-oxide-contaminated GaAs. PL enhancement is critically dependent on exposure time and pressure because of competition between plasma passivation and damage. Optimal exposure time and pressure are inversely related; thus, previous reports of ineffective passivation at room temperature result from overexposure at low pressure. Plasma treatment is effective in removing As to leave a Ga-rich oxide; removal of excess As increases the photoluminescence yield as the corresponding near-midgap-state density is reduced. Passivation is stable for more than a month. These results demonstrate the power of real time monitoring for optimizing plasma processing of optoelectronic materials

Materials and Reliability Handbook for Semiconductor Optical and Electron Devices

XVI, 616 p.online resource

Annealing Stability of NiO/Ga₂O₃ Vertical Heterojunction Rectifiers

The stability of vertical geometry NiO/Ga2O3 rectifiers during two types of annealing were examined, namely (1) the annealing of NiO only, prior to the deposition of the Ni/Au metal anode stack, and (2) the annealing of the completed device. The devices were annealed in oxygen for 1 min at a temperature of up to 500 °C. The results show that annealing at 300 °C can lead to the best performance for both types of devices in terms of maximizing the breakdown voltage and on–off ratio, lowering the forward turn-on voltage, reducing the reverse leakage current, and maintaining the on resistance. The surface morphology remains smooth for 300 °C anneals, and the NiO exhibits a bandgap of 3.84 eV with an almost unity Ni2O3/NiO composition