Miércoles, 17 de diciembre a las 15h00

Se invita a estudiantes y profesores a la conferencia que dará la
Srta ROSA DIAZ RIVAS
School of Material, Arizona State University.

Rosa Díaz es egresada de la Escuela de Ingeniería Física y actualmente está realizando el PhD en la universidad de Arizona-USA

Lugar : Facultad de Ciencias. Aula R1-430

TITLE: In-Situ catalytic growth of Gallium Nitride Nanowires.
AUTHORS (FIRST NAME, LAST NAME): Rosa E. Diaz1, Renu Sharma2, Subash Mahajan1,
Karalee Jarvis1
INSTITUTIONS (ALL):
1. School of Material, Arizona State University, Tempe, AZ, USA.
2. Center for Solid State Science, Arizona State University, Tempe, AZ, USA.

ABSTRACT BODY:
Group III nitride large band gap semiconductors have attracted special interest for optoelectronics devices such as blue-green light-emitting diodes (LED), blue-light laser diodes (LD), ultraviolet detectors, and electronic devices that work at high power, high frequency, and high temperature.
Multi-layer epitaxial structures required for various devices are generally grown on (0001) sapphire and silicon carbide substrates. Lattice mismatches between the III nitrides and these substrates result in high density of dislocations, which reduce the efficiency of the device. Despite all the efforts to reduce dislocation densities, the development of optimum devices still has not been achieved. One possible solution for this problem is to substitute these semiconductor epitaxial films by semiconductor nanowires, which present, in most cases, stress-free surfaces and similar or even better electrical and optical properties. One of the most common methods to synthesize semiconductor 1-D nanostructures is vapor-liquid-solid (VLS) catalytic growth. However, there is not a complete understanding of the growth mechanisms, the role of the catalysts, and the interface dynamics. This work involves an in-situ study of gallium nitride (GaN) nanowires formation in an environmental transmission electron microscope (ETEM) by
direct reaction of ammonia with Ga-Au liquid droplets on perforated silicon oxide membranes grids. In order to control and optimize the VLS growth, a series of reaction parameters, as well as different Ga/Au composition ratios, were applied. In addition, analytical studies were performed on GaN nanowires, including electron loss energy spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS).