Stability of (100)GaAs surfaces in aqueous solutions

Abstract
Abrupt (100) GaAs surfaces are observed to be stable against the development of pervasive microscopic roughness in strongly basic (pH 14) solutions but not in NH4OH and neutral H2O. Strong acids (pH 0) produce deep microroughness. The stability can be understood from the free energy of Ga ions in solution and the action of electrophilic bifunctional etching groups on the Ga–As bond.