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Title: Investigation of chemical wet-etch surface modification of Ga[sub 0. 5]In[sub 0. 5]P using photoluminescence, X-ray photoelectron spectroscopy, capacitance measurements, and photocurrent-voltage curves

Journal Article · · Journal of Physical Chemistry; (United States)
DOI:https://doi.org/10.1021/j100002a043· OSTI ID:6608424
; ; ; ; ;  [1]
  1. National Renewable Energy Lab., Golden, CO (United States)

Epitaxial Ga[sub 0.5]In[sub 0.5]P films, deposited lattice-matched to GaAs by atmospheric pressure organometallic vapor phase epitaxy, were subjected to various wet-etching processes and the resulting surface was characterized. The steady-state photoluminescence (PL) peak intensity was found to increase 5-fold with some etches, indicating lowered surface recombination rates as a result of etching. Average PL decay times estimated from time-resolved photoluminescence studies also exhibited a correspondingly significant enhancement. Capacitance-voltage and photocurrent-voltage measurements were carried out to investigate changes in energetics of the band edges or alteration in kinetics as a result of the treatments. High resolution X-ray photoelectron spectroscopy revealed a variation of the oxidized species of P, Ga, and In on the surface with etching and were correlated to the PL results. The amount of oxidized material on the surface was lowered after etching in concentrated H[sub 2]SO[sub 4], 1:20:1 HCl:CH[sub 3]COOH:H[sub 2]O[sub 2], and 1:20:1 HCl:H[sub 3]PO[sub 4]:H[sub 2]O[sub 2] and concurred with observations of a higher steady-state PL intensity and longer carrier lifetimes. A nitric acid or aqua regia etch on the other hand yielded an oxide-rich surface with diminished PL. 30 refs., 10 figs., 2 tabs.

OSTI ID:
6608424
Journal Information:
Journal of Physical Chemistry; (United States), Vol. 99:2; ISSN 0022-3654
Country of Publication:
United States
Language:
English