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Photoelectrochemical Process for Hydrogen Production
Published in Mu Naushad, Saravanan Rajendran, Abdullah M. Al-Enizi, New Technologies for Electrochemical Applications, 2020
A solar fuel based on molecular catalyst (cobaloxime) immobilized semiconductor was synthesized (Beiler et al. 2016). Here, III-V semiconductor, gallium phosphide (GaP) with the indirect bandgap of 2.26 eV was used. The two faces of GaP (100) and (111) were easily exposed to oxidation and corrosion. This can be avoided by stabilizing GaP with polyvinylimidazole (PVI) polymer. This material was used as the photocathode in PEC H2 generation. The light source used for PEC studies was AM 1.5 filters equipped 100 W Oriel Solar Simulator. Phosphate buffer (PBS) with pH 7 and 100 mV/s was used as the supporting electrolyte and scan rate, respectively. Figure 6.3 shows the linear sweep voltammogram of photoelectrodes with and without cobaloxime-modified GaP. As compared with unmodified electrodes, the photocurrent density of the modified electrode was greater at 0 V vs. RHE. The Iph of PVI-GaP electrodes was 0.32 ± 0.04 and 0.30 ± 0.08 mA cm−2. The Iph of Co-PVI-GaP electrodes was 0.89 ± 0.02 and 0.89 ± 0.03 mA cm−2 for the A- and B-faces, respectively. Thus, it shows that the electrodes with both A- and B-faces have identical current and voltage response. This photocurrent was also stable for 1 h.
G
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
gain-transfer measurement method common antenna gain measurement scheme in which the absolute gain of the antenna under test is determined by measuring its gain relative to a gain standard (i.e., antenna with accurately known gain). GaInN/AlInN rapidly evolving semiconductor heterostructure system with ability to emit light in the green and blue regions of the spectrum for long-lifetime LEDs and lasers. Galerkin's method in an integral equation technique used to solve a numerical electromagnetic problem, the method in which the expansion and testing functions are the same. gallium arsenide (GaAs) a composite widely used in the fabrication of active elements. gallium phosphide (GaP) (1) a semiconductor for high-speed electronics and that is part of the family of III-V compounds for semiconductor lasers.
Introduction
Published in J. R. Coaton, A. M. Marsden, Lamps and Lighting, 2012
The requirements for an LED of a pure single crystal material which can be doped both p-type and n-type are satisfied by many of the semiconductor III–V compounds. Some of the most important commercially available LEDs are based on gallium arsenide and gallium phosphide. The former ha? a direct band gap of 1.49 eV and is an efficient infrared electroluminescent emitter. Gallium phosphide has an indirect gap of 2.25 eV. They form a continuous solid solution over the entire arsenic-phosphorus range: the alloy gallium arsenide phosphide (GaAsP) can be tailored by adjusting the arsenic/phosphorus ratio to give intermediate band gaps and LEDs that emit the colours red, orange and yellow. Other alloys have been developed for high brightness red LEDs based on AlGaAs heterostructures where the p and n parts of the junction are made from different AlGaAs compositions. Gallium phosphide can be doped to give red and green LEDs, and gallium nitride and silicon carbide can be used to produce blue.
Band structure and chemical bonding of GaP: pressure-induced effects
Published in Phase Transitions, 2020
N. Bouarissa, H. Algarni, F. Mezrag, M. Ajmal Khan
Wide band-gap semiconducting compounds are important materials for creating semiconductor devices and for the development of new semiconducting materials [1–5]. Gallium phosphide (GaP) is a wide band-gap compound semiconductor material that possesses a zinc-blende structure with an indirect band-gap at room temperature [6–8]. It is odorless and insoluble in water. The material of interest has applications to electroluminescent devices [9]. This makes it one of the most commercial important III-V semiconductors. The preparation and growth of the material in question take place at the extreme ends of the temperature and pressure ranges which present particular challenges.