Solid-state Schottky barrier cell

The promise of photoelectrochemical devices of both the photovoltaic and chemical producing variety has been discussed and reviewed extensively.Cl,, 3,4) The criteria that these cells must meet with respect to stability, band gap and flatband potential have been modeled effectively and in a systematic fashion. However, it is becomirg clear that though such models accurately describe the general features of the device, as in the case of solid state Schottky barrier solar cells, the detailed nature of the interfacial properties can play an overriding role in determining the device properties. Some of these interface properties and processes and their potential deleterious or beneficial effects on electrode performance will be discussed. 

For p-n photovoltaic devices, the optimum band gap yields upper limit conversion efficiencies of about 25%. For solid state Schottky photovoltaic cells, the calculated maximum efficiencies are lower for the same semiconductor materials this is because the potential barrier heights (band bending) at the semiconductor-metal junctions are low compared with the semiconductor band gap. The upper limit efficiency for solid state Schottky cells is about 10-12%. 

Fig. 13. The short-circuit current carrier-collection efficiencies of an a-Si H/Pt Schottky-barrier cell in the annealed state A (solid line) and in the light-soaked state B (broken line). The measurements were carried out with 1-sun bias illumination.

We have extended the technique of Relaxation Spectrum Analysis to cover the seven orders of magnitude of the experimentally available frequency range. This frequency range is required for a complete description of the equivalent circuit for our CdSe-polysulfide electrolyte cells. The fastest relaxing capacitive element is due to the fully ionized donor states. On the basis of their potential dependence exhibited in the cell data and their indicated absence in the preliminary measurements of the Au Schottky barriers on CdSe single crystals, the slower relaxing capacitive elements are tentatively associated with charge accumulation at the solid-liquid interface. 

P. Panayotatos and H. C. Card, Recombination in the space-charge region of Schottky barrier solar cells, Solid State Electron. 23 (1980) 41-47. 

Schottky Barrier solar cells, submitted to Solid-State Electronics. 

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