Investigation of the galvanoluminescent effects of oxide aluminum layers obtained by means of anodization in oxalic acid

Abstract

The results of an investigation of the effect of anodization current density and electrolyte temperature in an electrolytic chamber on the thickness of the barrier part of the porous oxide layer, anodization voltage U, and galvanoluminescence intensity L are presented. The interdependence of these variables was determined and the shape of the dependence of galvanoluminescence L on layer formation voltage U, L=A*(exp(U/B)-1), was obtained, being the shape arrived at by Van Geel [1]. B is a constant which comprises the ionization coefficient [2,3] and anodization rate [4], whereas B amounted to 9.36 V in the experiment. A is the normalization factor dependent only on the temperature t. The normalization factor includes the initial electron current at the electrolyte-oxide boundary, the effective section for ionization, and the effective section for exitation of the luminescent center by means of the electron-avalanche electron. The intensity of galvanoluminescence L and oxide layer formation voltage U were found to decrease with the increase in temperature t. Strictly defined experiment conditions are described in detail order to avoid different interpretations of the measurement results.