Photoluminescent Properties of p-GaAs Electrodes Related to the 'Photocurrent Anomaly': Determination of Surface Electron-Capture Velocities and Depletion Widths in Photoelectrochemical Cells.
Abstract
Steady-state photoluminescence (PL) measurements have been used to determine depletion widths W and surface electron-capture velocities S for p-GaAs electrodes in aqueous acidic electrolytes. Electrodes subjected to slow cycling of applied potential (10 mV/s) exhibit a hysteresis in PL intensity in the photocurrent anomaly (PA) potential regime, characterized by negligible photocurrent at voltages up to approx. 0.5 V negative of the flatband potential approx. 0.1 V vs. SCE). A marked hysteresis in S values is observed in the PA potential regime of -0.1 to -0.4 V vs. SCE. Estimated S values are high, approaching 10 to the 7th power cm/s, but decrease significantly during anodic-going scans. Variations in W between -0.1 and -0.8 V vs. SCE indicate that strong Fermi-level pinning does not obtain. Electrode operation under a pulsed potential program (-0.05 to -1.00 V vs. SCE) caused a transient reduction in S of approximately an order of magnitude. Keywords: Photoluminescence; Dead layer model; Depletion width; Surface electron capture velocity; Photoelectro-chemical cells; Gallium arsenides.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 08, 1987
- Accession Number
- ADA182963
Entities
People
- Arthur B. Ellis
- Christopher S. Mcmillan
- Phelps B. Johnson
- William S. Hobson