A Model for Pore Growth in Anodically etched Gallium Phosphide

RICCI, PIER CARLO;SALIS, MARCELLO;ANEDDA, ALBERTO

2005-01-01

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Abstract

The electrochemical etching process of porous gallium phosphide was studied by means of the characteristic current–potential sI–Vd curves. Measurements were performed in H2SO4 0.5-M aqueous solution both in the dark and by illuminating the samples with the 351-nm line of an argon laser. Raman spectroscopy was applied to investigate the surface morphology of the samples prepared under different anodizing conditions within the potentiostatic regime. Based on a few reasonable assumptions, a simple model of pore growth is proposed. The enhancing effect in current intensity due to the branching of pores and the opposite effect due to a concomitant decrease in the effective cross area available for carrier transport are accounted for to explain the main features of the recorded I–V curves.