Experimental determination of integral and local density of states of InAs quantum dots in GaAs/AlGaAs heterostructure by using BEEM/BEES

Year: 2013

 Jan Vaniš, Ph.D.

Cooperation: Institute of Physics ASCR, Institute of Information Theory and Automation ASCR

We invented a method of spatial mapping of the ballistic current so that the ballistic electron microscope and spectroscope can be used to consistently map the density-of-states in quantum dots (QD). QD is a semiconductor nanocrystal placed in another type of semiconductor with a higher bandgap. QD can confine electrons with discrete energy levels similar to atoms. This is used for new optoelectronic devices, such as low thresholds lasers, infrared detectors and high-density optical memories.

On the left: Map of density of state in SAQD for energy 0.552 eV. On the right: Integral mean density of states characteristic in the whole examined SAQD including Ib-V characteristic with denoted split of electron level.

Publication:

1. Walachová, Jarmila ; Zelinka, Jiří ; Leshkov, Sergey ; Šroubek, Filip ; Pangrác, Jiří ; Vaniš, Jan. Integral and local density of states of InAs quantum dots in GaAs/AlGaAs heterostructure observed by ballistic electron emission spectroscopy near one-electron ground state. .i.Physica E: Low-Dimensional Systems and Nanostructures./i., 2013