ON THE ETCHING OF GAP SINGLE-CRYSTALS IN AQUEOUS BROMINE SOLUTIONS

The etch rate of n- and p-GaP single crystals was measured in aqueous Br2 solutions, using a flow-cell set-up. The etching process was found to occur by a chemical mechanism, involving the formation of radical decomposition intermediates. The difference in etching kinetics between the (1̄1̄1̄)- and the (111)-face resulted in a difference in the morphology of the surface after etching. Incorporating the GaP crystals in an electrochemical cell gave a strong interrelationship was found between the cathodic reduction of Br2, the chemical and the anodic etching of GaP. © 1990.