We have investigated the THz range magneto-optical response of ultralow carrier density films Sb$_2$Te$_3$ using time-domain polarimetry. Undoped has a chemical potential that lies inside bulk valence band. Thus its topological is masked by carriers. However, with appropriate buffer layer engineering and doping, thin can be grown extremely low electron or hole densities. The samples show unusua...

We refine a technique used by B. Boyce to change the carrier concentration level of thin YBa2Cu3O7-δ (YBCO) films. The purpose of this is to eventually study the superconductor to insulator transition that takes place in YBCO as carrier concentration level decreases. Introduction. For high carrier densities, YBCO is a d-wave superconductor, and its superfluid density has either a linear or a qu...

We report a method to promote photoluminescence emission in graphene materials by enhancing carrier scattering instead of directly modifying band structure in multilayer reduced graphene oxide (rGO) nanospheres. We intentionally curl graphene layers to form nanospheres by reducing graphene oxide with spherical polymer templates to manipulate the carrier scattering. These nanospheres produce hot...

Title of dissertation: THEORY OF GRAPHENE TRANSPORT PROPERTIES Qiuzi Li, Doctor of Philosophy, 2013 Dissertation directed by: Professor Sankar Das Sarma Department of Physics Graphene is of great fundamental interest and has potential applications in disruptive novel technologies. In order to study the novel phenomena in graphene, it is essential to understand its electron transport properties ...

5-Fluorouracil (5-FU) is an anticancer drug. In this work, we have investigated the electronic properties and topological analysis of interaction between 5-FU and carbon nanocone and BN nanocone. The structural stability of isomer complexes of 5-FU with carbon nanocone and BN nanocone have been investigated for two position of interactions. We have found that the most stable complexes are forme...

The carrier distribution functions in a semiconductor crystal in the presence of a strong optical field are obtained. These are used to derive expressions for the gain dependence on the carrier density and on the optical intensitythe gain suppression effect. A general expression for high order nonlinear gain coefficients is obtained. This formalism is then used to describe the carrier and power...

We investigated the high-carrier screening of macroscopic polarization fields in GaN quantum wells (QWs) using a variational wave function for electrons and holes. In particular, we studied of the influence of free-carrier screening on the photoluminescence (PL) energy emission and carrier lifetime in the QW. We show that the energy transition between electrons and holes are explained well by t...

The electronic structure of graphene causes its charge carriers to behave like relativistic particles. For a perfect graphene sheet free from impurities and disorder, the Fermi energy lies at the so-called ‘Dirac point’, where the density of electronic states vanishes. But in the inevitable presence of disorder, theory predicts that equally probable regions of electron-rich and hole-rich puddle...