Papers by Keyword: SNOM

Abstract: We develop a nanoslit to detect a small number of neutral atoms in the ground state. The detection scheme of using two-step photoionization is very sensitive and the use of nanometric near-field lights leads to an ultrahigh spatial resolution. An edge-sharpened nanoslit is fabricated with FIB milling. Considering the case of detecting Rb atoms, the polarization-dependent spatial distribution of near-field light generated at the nanoslit by total-internal reflection of a 476.5-nm Ar-ion laser beam is obtained with a scanning near-field optical microscope. Based on the experimental results, the ionization efficiency is estimated for both s-polarization and p-polarization. We also discuss the discrepancy between the experimental value and the numerical one obtained from the finite difference time domain simulations in the p-polarization case.

Abstract: We have prototyped illumination-collection mode scanning near-field optical microscopy (SNOM) and near-field Raman spectroscopy (NFRS) with gold inner-covered aperture-less pyramidal probe in order to study the possibility to detect optical images, and Raman spectrum and Raman peak shift for stress distribution in Si device with high resolution of about 10 nm.

Abstract: The formation of metal/diamond Ohmic contacts is essential to most electronic devices. In order to form a good Ohmic contact to diamond a carbide-forming metal such as Ti or Cr is necessary. In this study, Cr/Au contacts to heavily boron-doped single crystal CVD diamond were fabricated by subsequent deposition of Cr and Au. The surface morphology and specific contact resistance of diamond/Cr/Au contacts has been investigated. The reaction between the Cr metal and the diamond during annealing gives an improved specific contact resistance. However, this reaction also causes a significant change in the surface morphology. The surface morphology of singlecrystal diamond is shown to greatly influence the properties of metal contacts to diamond. Shearforce mode atomic force microscopy (AFM) investigations have been used to examine the diamond surface before metallization, and after removing the metal contact. The initial diamond surface was predominantly smooth, apart from some scratches from the polishing process. Surface RMS roughness values of around 0.4nm were found. Correlation between surface morphology and contact resistance has been found, with rougher surfaces exhibiting a barrier to conduction. An understanding of the contact formation process is an essential step in achieving high quality Ohmic contacts which are vital in the fabrication of high quality diamond devices.