Cecilia Noguez's

Research Interests

Optical properties of nanoparticles and Surface Enhanced Spectroscopies The fabrication of nanostructures requires a deeper understanding of the physical phenomena involved at this scale. Low-dimensional quantum structures have shown to have unique optical and electronic properties, which have been employed in the fabrication of new opto-electronic devices. In particular, the shape and size of low-dimensional structures are crucial parameters to determine their physical properties. It is well known that the distribution of electronic states on a nanostructure depends on its size, and the confinement potential acting on the electrons is associated to its shape. Therefore, the exact knowledge of the size and shape of a nanostructure is of decisive importance in the development of the science and technology at the nanometer scale. Furthermore, the characterization of these parameters are important issues either in fundamental research or in technological applications, covering from growth and characterization to device processing. The chiral nature of the clusters, which means they exist in distinct right-handed and left-handed variations, dramatically affects the way in which they absorb polarized light. This optical effect had been predicted theoretically to occur in metal nanostructures, and it has been observed experimentally in a special class of clusters.

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Silver nanocube of 7 nm

Optical properties of isolated and supported metal nanoparticles, Cecilia Noguez, Optical Materials 27, 1204 (2005).
Optical absorbance of Colloidal suspensions of silver polyhedral nanoparticles, A. L. Gonzalez, Cecilia Noguez, G.P. Ortiz, and G. Rodriguez-Gattorno, J. Phys. Chem. B 109, 17512 (2005).
Optical Properties of Metal Nanoparticles with Arbitrary Shapes, I. O. Sosa, C. Noguez, R. G. Barrera, J. Phys. Chem. B 107, 6269 (2003).
Substrate effects on the optical properties of a spheroidal nanoparticle, C.E. Roman, C. Noguez, R. G. Barrera, Phys. Rev. B 61, 10427 (2000).

Optical and Electronic properties of surfaces Low-dimensional quantum structures have shown to have unique optical and electronic properties, being important in the fabrication of new opto-electronic devices. III-V semiconductor compounds have demonstrated to be important in the development of new light emitters and detectors. In particular, Indium compounds, like InAs and InSb, are good infrared detectors due to their small bulk-band gap. Most of modern opto-electronic devices are fabricated growing monoatomic layers on a semiconductor substrate using epitaxial techniques. The epitaxial growth depends on the ambient conditions as well as in the atomic and electronic properties of the surface of the substrate. Therefore, the continuous development of semiconductor heterostructures and other structures at the nanometer scale, makes evident the need for a detailed theoretical and experimental understanding of semiconductor surfaces.

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Reflectance Anisotropy Spectrum of InAS (110)

Electronic structure and Reflectance Anisotropy spectrum of InAs(110), X. Lopez Lozano, O. Pulci, C. Noguez , K. Fleischer, W. Richter and R. Del Sole, Physical Review B 71, 125337 (2005).
Origin of optical anisotropies of non-polar GaN surfaces, C. Noguez, Phys. Rev. B 62, 2681 (2000).
Theoretical and experimental optical spectroscopy study of hydrogen adsorption at Si(111)-7x7, C.Noguez, C. Beitia, W. Preyss, A.I. Shkrebtii, M. Roy, Y. Borensztein, R. Del Sole, Phys. Rev. Lett. 76, 4923 (1996).

Casimir effect in real materials at the nanometer scale For many years the Casimir effect was little more than a theoretical curiosity. But interest in the phenomenon has blossomed in recent years. Experimental physicists have realized that the Casimir force affects the workings of micromachined devices, while advances in instrumentation have enabled the force to be measured with ever-greater accuracy. The new enthusiasm has also been fired by fundamental physics. Many theorists have predicted the existence of ``large’’ extra dimensions in 10- and 11-dimensional unified field theories of the fundamental forces. These dimensions, they say, could modify classical Newtonian gravitation at sub-millimetre distances. Measuring the Casimir effect could therefore help physicists to test the validity of such radical ideas.

Spectral Representation of the Casimir Force Between a Sphere and a Substrate, C. Roman-Velazquez, C. Noguez, C. Villarreal, R. Esquivel-Sirvent, Phys. Rev. A 69, 042109 (2004).
Dispersive force between dissimilar materials: Geometrical effects , C. Noguez, C.E. Roman-Velazquez, Physical Review B 70, 195412 (2004).
High-multipolar effects on the Casimir force: the non-retarded limit, C. Noguez, C. E. Roman-Velazquez, C. Villarreal y R. Esquivel-Sirvent, Europhysics Letters 67, 191 (2004).

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Cecilia Noguez

Professor of Physics

Instituto de Fisica

Universidad Nacional Autonoma de Mexico

Apartado Postal 20-364

Mexico DF 01000, MEXICO

Phone: (++52 55) 5622 5106

Secretary: (++52 55) 5622 5010

Fax: (++52 55) 5616 1535