Photoreflectance was used to study the properties of (100) surfaces which had been exposed to a Cl2/Ar plasma and subsequently passivated with P2S5. The plasma-etching shifted the Fermi level of p-type material from near to the valence band to the mid-gap, but had no effect upon n-type material. For ion energies below 250eV, the post-etch passivation removed the surface-etching damage and restored the properties to pre-etch conditions. At ion energies above 250eV, the etching produced sub-surface defects which could not be chemically passivated.

Electronic properties of GaAs surfaces etched in an electron cyclotron resonance source and chemically passivated O.J.Glembock, J.A.Tuchman, J.A.Dagata, K.K.Ko, S.W.Pang, C.E.Stutz: Applied Physics Letters, 1998, 73[1], 114-6