Fundamental Properties of Chalcogenide-Type Nanostructures

Seminar series
Physical Chemistry Seminar
Mon, May 16 4:00pm
2033 Young Hall
Speaker Prof. Jia Grace Lu
University of Southern California
Dept. of Physics and Astronomy and Electrical Engineering

Abstract: This presentation will first discuss the cadmium chalcogenide nanowires. Cadmium chalcogenides have direct band gaps that span from infrared to visible range. They possess excellent light absorption capability and superior photosensitivity, and thus are outstanding materials for developing nanoscale electronic and optoelectronic devices. As the device applications strictly depend on their intrinsic material properties, therefore, it is of paramount importance to elucidate their fundamental physical properties. I will present the basic structural, electrical, and optical properties, respectively, of CdS and CdTe nanowires. 

Next, I will describe the topological insulating nature of Sb2Te3 nanowires grown by chemical vapor deposition with different cross-sectional areas. The magnetoresistance measurements is supported by nanoscale angle-resolved photoemission spectroscopy, indicating that the observed Aharonov-Bohm type oscillations in the presence of parallel magnetic field arise from dominating TI surface transport in the p-type Sb2Te3 nanowires. The analysis of the magnetoconductance data with a magnetic field perpendicularly oriented to the wire axis reveals universal conductance fluctuations with a characteristic correlation field Bc The extracted coherence length and the temperature dependence of the conductance fluctuation provide information on the coherent-transport of TI surface states and the quasi-one-dimensional character of the transport along the wire axis.