Quantum chemical study of the initial surface reactions of atomic layer deposition GaAs for photonic crystal fabrication

III-V materials such as GaAs, GaP, and InP are deposited by atomic layer depostion (ALD) to form inverse opal due to their modifiable intrinsic optoelectronic properties, thus active photonic devices are possible to fabricate. ALD GaAs on the hydroxylated SiO2 surface was investigated under the framework of density functional theory. Our calculation results show that both half-reactions are thermodynamically and kinetically favored, exothermic by 33.73 and 25.90 kcal/mol compared to the reactants. However, longer AsH3 pulse time during the second half cycle of ALD procesis recommended since there is a high activation energy barrier existing in the second half cycle. (C) 2008 American Institute of Physics.