Chemical treatment and Fermi-level pinning of CuInS2 and InP photocathodes
- 1 April 1988
- journal article
- conference paper
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 63 (7) , 2420-2424
- https://doi.org/10.1063/1.341036
Abstract
The photovoltage variation with redox potential ERed is investigated on p‐InP and p‐CuInS2 for various surface treatments. Etching and ion chemisorption are shown to successively improve CuInS2 photovoltages VPh resulting in a slope of ∼1 of VPh vs ERed. The respective densities of states are determined using a model calculation yielding Ds ≊6×1011 states cm−2 eV−1 and Ds ≊1.2×1014 states cm−2 eV−1 for the unpinned and pinned situation, respectively. Good agreement between the calculated voltage drop in the Helmholtz layer due to CuInS2 Fermi‐level pinning (FLP) and the missing photovoltage is obtained in a simple model calculation based on the surface state charge density. InP photocathodes show a VPh vs ERed dependence in the dark, depending on pretreatment which is attributed to a chemical reaction that inhibits Fermi level equilibration. Positive from −0.4 V (SCE) VPh is independent of ERed for polished and etched surfaces. The independence is explained assuming a dynamic equilibrium between semiconductor and solution without band‐edge shifting. At the potential where p‐InP solar cells are operated (−0.47 V vs SCE), the electrodes behave as unpinned.This publication has 33 references indexed in Scilit:
- The Fermi level and the redox potentialThe Journal of Physical Chemistry, 1985
- Fermi levels in electrolytes and the absolute scale of redox potentialsApplied Physics Letters, 1983
- Fermi level pinning of p-type semiconducting indium phosphide contacting liquid electrolyte solutions: rationale for efficient photoelectrochemical energy conversionJournal of the American Chemical Society, 1981
- Semiconductor electrodes. 24. Behavior of photoelectrochemical cells based on p-type gallium arsenide in aqueous solutionsJournal of the American Chemical Society, 1980
- The concept of Fermi level pinning at semiconductor/liquid junctions. Consequences for energy conversion efficiency and selection of useful solution redox couples in solar devicesJournal of the American Chemical Society, 1980
- Photoreduction at illuminated p-type semiconducting silicon photoelectrodes. Evidence for Fermi level pinningJournal of the American Chemical Society, 1980
- The role of the interfacial layer in Schottky barrier solar cellsJournal of Physics D: Applied Physics, 1979
- Fermi Level Position at Metal-Semiconductor InterfacesPhysical Review B, 1964
- Surface States and Rectification at a Metal Semi-Conductor ContactPhysical Review B, 1947
- Halbleitertheorie der SperrschichtThe Science of Nature, 1938