As the critical dimensions of many devices, especially electronics, continue to become smaller, the ability to accurately analyze the properties at ever smaller scales becomes necessary. Optical techniques, such as confocal microscopy and various spectroscopies, have produced a wealth of information on larger length scales, above the diffraction limit. Scanning probe techniques, such as scanning tunneling microscopy and atomic force microscopy, provide information with an extremely fine resolution, often on the order of nanometers or angstroms. In this document, plasmon coupling is used to generate large signal increases, with clear future applications toward scanning probe optical spectroscopies. A variation on scanning tunneling microscopy is also used to study the surface structure of environmentally interesting nanoparticles. Traditional Raman spectroscopy is used to examine doped graphene, which is becoming a hot material for future electronic applications.

The electronic structures at the hetero interface of Poly(3-hexylthiophene): methanofullerene (P3HT:PCBM) have a great improvement on the solar cell efficiency due to the formation of bicontinuous nanoscaled phase separation which will enhance charge separation and carrier transport. In the present work, cross-sectional scanning tunneling microscopy and scanning tunneling spectroscopy measurements are utilized to obtain the in-situ atomic-scale band structure across the interface between P3HT and PCBM directly. The distribution of PCBM volume concentration of organic films was also analyzed and discussed in the work.

The electronic structure at interface between two insulators LaAlO3 and SrTiO3 has been investigated by using scanning tunneling microscopy and spectroscopy. The atomic-scale interfacial band structure is also demonstrated in the work with the consideration of the tip-induced band bending effect. Experimental results indicate that the magnitude of the built-in field across LaAlO3 is 0.075¡Ó0.005 V/Å. The band bending on SrTiO3 side at the heterointerface is observed. The band downshift of SrTiO3 side at the interface is 0.1 eV with ~1 nm decay length.

In this work, the interfacial electronic property between N-type LaAlO3/TiO2-SrTiO3 has been investigated by using scanning tunneling microscopy and spectroscopy (STM/S). With the consideration of the tip-induced band bending effect during STM measurements and in conjunction with the three-dimensional theoretically analysis, the schematic band structure of the hetero-structured SrTiO3/LaAlO3 is also revealed. Results indicate that the magnitude of the built-in field on the LaAlO3 is (30¡Ó5) mV/Å. The band bending on SrTiO3 side at the heterointerface is also observed. The band downshift of SrTiO3 side at the interface is 0.31 eV with about 0.8 nm decay length.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 95-100).

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 87-91). Available also in a digital version from Dissertation Abstracts.

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An STM head based on the design of Besocke was designed and constructed to have superior vibrational and thermal stability in order to produce very high resolution images. The vibrational properties and thermal properties of the head design are quantitatively analyzed and compared to the actual performance achieved. With this new STM head, we were able to implement spectroscopic dI/dV imaging techniques (conductance imaging) to observe electronic features on surfaces. Using this conductance imaging, benzene and chlorobenzene on the Si(111)7x7 surface were studied. We also present the first solid evidence that confirms that the rest atom is involved in the bonding of benzene to this surface. We show that conductance imaging does indeed show variations in the electronic structure of the surface with adsorbates, illustrating that this technique has strong potential for assigning binding sites. / xiv, 155 leaves ; 29 cm.

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