Comparison of the Chemical Passivation of GaAs, In0.53Ga0.47As, and InSb with 1-Eicosanethiol

Abstract

Self-assembled 1-eicosanethiolate layers were deposited on the oxide-free (100) crystal planes of GaAs, In0.53Ga0.47As, and InSb to protect the surfaces. The layer prevented re-oxidation in air for 30 min on GaAs but only 8 min on In0.53Ga0.47As based on the O 1s x-ray photoelectron spectroscopy state. The layer protected InSb from reoxidation for only 4 min based on the O Auger state. Well-ordered monolayers formed on GaAs and In0.53Ga0.47As based on transmission Fourier transform infrared (FTIR) spectroscopy. A partially ordered layer was formed on InSb based on attenuated total reflection FTIR. The increased reoxidation rate of InGaAs and InSb is due to the larger lattice parameter of these surfaces and their In content, which forms weaker bonds to S, Ga, and Sb compared to Ga bonding to As and S.