A flat epitaxial silver film on a gallium arsenide [GaAs(110)] surface was synthesized in a two-step process. Deposition of a critical thickness of silver at low temperature led to the formation of a dense nanocluster film. Upon annealing, all atoms rearranged themselves into an atomically flat film. This silver film has a close-packed (111) structure modulated by a "silver mean" quasi-periodic sequence. The ability to grow such epitaxial overlayers of metals on semiconductors enables the testing of theoretical models and provides a connection between metal and semiconductor technologies.

Abstractin this paper we present results on the stability and lateral resolution capability of carbon

We report an innovative approach that combines nanopatterning and nanomaterials synthesis with traditional silicon micromachining technologies for large-scale fabrication of carbon nanotube (CNT) probe tips for atomic force microscopy imaging applications. Our batch fabrication process has produced 244 CNT probe tips per 4-in. wafer with control over the CNT location, diameter, length, orientation, and crystalline morphology. CNT probe tips with diameters ranging between 40 and 80 nm and lengths between 2 and 6 µm are found to be functional probe tips with no need for shortening. This reliable and true bottom-up wafer scale integration and fabrication process provides a new class of high performance nanoprobes. Preliminary AFM imaging results show that the CNT probe tips are strong, wear-resistant, and capable of highresolution and critical-dimension imaging.

We show a direct determination of the charge state of surface As vacancies on p-type GaAs͑110͒ using scanning tunneling microscopy. This method utilizes the compensation between the local band bending resulting from the As vacancy and the p-type dopant whose charge states are known a priori. Detailed analysis shows a one-to-one compensation between the dopant-related and As-vacancy-related features, indicating that the As vacancy has a charge of ϩ1. This method can be extended to determine quantitative charge states of other point defects ͑positive or negative͒.