P-GaAs

Koinuma M and Uosaki K 1996 Atomic structure of bare p-GaAs(IOO) and electrodeposited Cu on p-GaAs (100) surfaces in H2SO4 solutions An AFM study J. Eiectroanai. Chem. 409 45-50... 

The photolytic reduction of N2 at TiO -suspensions was at first reported by Schrauzer et al. Small amounts of NH3 and N2H4 were obtained as products. The highest activity was found with anatase containing 20-30 % rutile. Very low yields were also obtained with p-GaP electrodes under illumination It is much easier to produce NH3 from NO -solutions at CdS- and Ti02-particles using S -ions as hole scavengers . Efficiencies are not reported yet. Recently the formation of NH3 from NO was observed at p-GaAs electrodes under illumination. In this case NH3-formation was only found in the presence of transition metal ions or their complex with EDTA. 

Figure 7. Quantum efficiency versus potential at various p-type semiconductors in a DMF-0.1 JVf TBAP solution containing 5% water under a C02 atmosphere. Monochromatic light of 600 nm was used for p-Si, p-InP, p-GaAs, and p-CdTe, while light of 400 nm was used for p-GaP.103 Scan rate 0.1 V/r...

Fig. 17. LHeT absorption of the Si-related LVMs in p+-GaAs Si after holes capture by (a) electron irradiation-induced effects and (b) deuterium-related neutralizing complexes. The spectral resolution is 0.1 cm1. J. Chevallier el al., Mat. Res. Soc. Symp. Proc. 104, 337 (1988). Materials Research Society. 

N. K. Dutta, Radiative Transitions in GaAs and Other III-V Compounds R. K. Ahrenkiel, Minority-Carrier Lifetime in III-V Semiconductors T. Furuta, High Field Minority Electron Transport in p-GaAs M. S. Lundstrom, Minority-Carrier Transport in III-V Semiconductors R A. Abram, Elfects of Heavy Doping and High Excitation on the Band Structure of GaAs D. Yevick and W. Bardyszewski, An Introduction to Non-Equilibrium Many-Body Analyses of Optical Processes in III-V Semiconductors... 

Thapar R, Rajeshwar K (1983) Mott-Schottky analyses on n- and p-GaAs/room temperature chloroaluminate molten-salt interfaces. Electrochim Acta 28 195-198... 

There are several non-oxide semiconductor electrodes that have been studied for use in photoelectrochemical cells for water splitting. Materials used as photocathodes include p-Si, p-lnP, p-GaAs, and p-CdTe. Materials used as photoanodes include n-Si, n-InP, n-GaAs, n-CdTe and n-CdSe. Similar to CdS, unfortunately most of these non-oxide semiconductors undergo photocatalytic corrosion under the conditions of oxygen evolution. 

Khader MM, Nasser SA, Hannout MM, El-Dessonki MS (1993) Photoelectrochemical dissociation of water at copper-doped p-GaAs electrodes. Int J Hydrogen Energy 18 921-924... 

Khader MM, Hannout MM, ElDessouki MS (1996) Catalytic effects for hydrogen photogeneration due to metallic deposition on p-GaAs. Int J Hydrogen Energy, 21 547-553... 

Khader MM, Saleh MM (1999) Comparative study between the photoelectrochemical behavior of metal loaded n- and p-GaAs. Thin Solid Films 349 165-170... 

It is known that the photoelectrochemical cell (PEC), which is composed of a photoelectrode, a redox electrolyte, and a counter electrode, shows a solar light-to-current conversion efficiency of more than 10%. However, photoelectrodes such as n- and p-Si, n-and p-GaAs, n- and p-InP, and n-CdS frequently cause photocorrosion in the electrolyte solution under irradiation. This results in a poor cell stability therefore, many efforts have been made worldwide to develop a more stable PEC. 

Fig. 3.41 Carrier concentration p versus pressure of As gas, for the crystals (ZA, ZB, ZC) prepared by reheating Zn-doped p-GaAs at 900, 1000, and 1100...

Figure 4.4 shows the surface band positions of some typical semiconductors in aqueous electrolytes (pH 7), calculated from the experimentally determined C/ft, compared with the redox levels of some important redox reactions. It is known that the U for most semiconductors, such as n- and p-GaAs, n- and p-GaP, n- and p-InP, n-ZnO, n-Ti02, and n-Sn02, in aqueous electrolytes is solely determined by the solution pH and shifts in proportion to pH with a slope of -0.059 V/pH.3,4) This is explained by the adsorption equilibrium for H+ or OH- between the semiconductor surface and the solution, for example,... 

Fig. 2.6 Current-potential curves for (A) p-InP, (B) p-GaAs, and (C) p-Si electrodes in 0.3 M TBAP in methanol (40 atm C02) (b) in the dark and (a, c) under illumination. Curves a and c correspond to the behavior corrected and uncorrected for ohmic losses, respectively. Curve d was obtained for a metallic Cu electrode. (QRE stands for quasi-reference electrode).

Figure 9. Model for splitting of surface states upon chemisorption of Rus on n-and p-GaAs.

Both, Beley et al. and Petit et al. reported the reduction of C02 to CO using Ni(cyclam)2+ catalysts in aqueous solution at p-GaAs and p-GaP photoelectrodes [121-123]. Here, the faradaic yields for CO approached 100%, at potentials of —1.0V and -0.44V (versus SCE), respectively, although carbon deposits on the surfaces of the electrodes led eventually to a degradation of the system. 

Fig. 10.5. Linear sweep voltammetry of illuminated p-GaAs in 1 M H2S04. (a) Before etching (b) after etching (c) after evolving H2 15 min scan speed, v= 100 mV s-1 (d) under dark conditions. (Reprinted from J.O M. Bockris,...

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