Formation of visible light emitting porous GaAs micropatterns

Pore growth on n-type GaAs (100) can be initiated in 1 M HCl solution by electrochemical polarization of the material anodic to a critical potential value-the pore formation potential (PFP). At surface defects, however, the PFP is significantly lower (shifted cathodically). Focused ion beam, implantation of Si++ was used to create defined patterns in the substrate. At these implant sites, the growth of porous GaAs was selectively achieved by polarization below the overall PFP. From the porous GaAs patterns visible photoluminescence at green-yellow wavelengths can be observed. This technique, thus, allows the production of light emitting porous GaAs micropatterns of arbitrary shape by a direct writing process. (C) 1998 American Institute of Physics.