Speaker: Sergio MM Coelho (pdf poster, slides) 
Department of Physics, University of Pretoria, South Africa. (Visitor from September 23 to October 14, 2014)
With JFR Archilla and F. Danie Auret.

Date and premises: Facultad de Física, 5th floor: Monday, October 7, 2013, 12:30 a.m.

Language: English

Abstract:

Modification of the crystal lattices of various semiconductors by subthreshold events, as creation and annealing of point defects, has been reported by a few groups (Chen & MacKay, 1968,Auret& Mooney, 1984)from the 1960’s until the present. These observations have been made in great detail with techniques like deep level transient spectroscopy (DLTS) but there is still much that needs to be clarified. The agent that modifies the crystal structure has often not been identified and then it is also unclear how packets of energy that can sometimes be as small of 2 eV can travel some μm deep into the material while still retaining enough energy or the order of 1eV to cause changes in the crystal.

This presentation will consist of a brief description of DLTS, a technique capable of detecting small changes in the structure of semiconducting materials, followed by why germanium was chosen by the authors as the material of choice for these studies. An experiment will be described that induced such changes deep in antimony doped germanium as well as a possible reason why this occurred. This phenomenon may hold the key to developing defect free material for future applications.

Organized by JFR Archilla and the Group of Non Linear Physics (GFNL) of the University of Sevilla, Spain.