REFLECTANCE AND REFLECTANCE ANISOTROPY MEASUREMENTS OF THE PHOTOELECTROCHEMICAL DEPOSITION OF GOLD ON P-TYPE GALLIUM-ARSENIDE (100) ELECTRODES

The photoelectrochemical deposition of gold on p-type GaAs has been monitored in situ via the total reflectance response and reflectance anisotropy of the nascent surface. It is demonstrated that the former method probes the macroscopic deposition rate while the latter method probes surface ordering in the growing layer. For the system studied here, the RA data are most consistent with a highly anisotropic initial gold layer, such as may be expected from a single-crystalline film. This proposal is shown to be in good agreement with electron diffraction data for the GaAs/Au interface, which indicate that the initial gold deposit adopts a (110) orientation in which the lattice parameter of the gold film matches that of the GaAs (100) substrate.