General Description of Non-oxide Semiconductors

This chapter considers photo-electrodes consisting of non-oxide semiconductors, alone and in combination with oxide semiconductors for water splitting. 

Various inorganic semiconductors (p-type and/or n-type nonoxide semiconducting materials) sucb as amorphous or crystalline silicon (a-Si or c-Si), gallium arsenide (GaAs), cadmium telluride (CdTe), gallium phosphide (GaP), indium phosphide (InP), copper 

Cadmium sulfide (CdS) is one of the most intriguing nonoxide semiconductors due to its sufficiently negative flat band potential (-0.66 V at pH 7) and optical absorption to 520 nm (bandgap = 2.4 eV), however it suffers from anodic 

These systems are based on immersion of two photoactive electrodes in an electrolyte solution with connection via an external circuit. An overall solar-spectrum hydrogen conversion efficiency of 0.25% was found at zero bias for the n-Ti02/p-GaP cell. Nozik further designed a new type of cell, so-called photochemical diodes that do not require external wires and functions without electrical bias [26]. This device [26], consisting of a small sandwich-like structure, Fig.7.2, such as Pt/n-GaP, and n-Ti02/p-GaP connected through ohmic contacts, when suspended in an appropriate electrolyte causes decomposition of water upon exposure to light. 

Incorporating metal catalysts, such as platinum, ruthenium, cadmium, gold, vanadium, etc. on the surface of p-type 

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