Charge carrier traffic at self-assembled Ge quantum dots on Si
Journal article, 2013

Germanium quantum dots (QDs) have been characterized by deep level transient spectroscopy (DLTS) and capacitance versus voltage (C-V) technique. Two types of dots, grown by molecular beam epitaxy (MBE) at different temperatures, were investigated and assessed with respect to morphological properties. Samples with dots grown at 350 degrees C, were designed as n(++)-p-p(++) silicon junctions with the QDs positioned in the depleted p-region, while a second type of samples were Shottky diodes based on medium doped silicon with the QDs prepared at 550 degrees C and positioned in the Schottky depletion region. From the combined results of temperature scanned and frequency scanned DLTS, and by varying hole filling levels of the QD potentials, the energy distribution of states in the QD potentials were investigated. A wider distribution was found for the low-temperature QDs, probably related with a larger variation of size. By using a technique for separating tunneling and thermal hole emission, the average thermal activation energy for emitting holes to the valence band was found close to 0.40 eV for both types of QDs.

Surface morphology

Electronic transport in quantum dots

Quantum confined energy states

Self-assembled Ge/Si quantum dots

Molecular beam epitaxy

Deep level transient spectroscopy

Author

M Kaniewska

Instytut Technologii Elektronowej (ITE)

Olof Engström

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

A Karmous

Universität Stuttgart

M Oehme

Universität Stuttgart

Göran Petersson

Chalmers, Microtechnology and Nanoscience (MC2), Nanofabrication Laboratory

E Kasper

Universität Stuttgart

Solid-State Electronics

0038-1101 (ISSN)

Vol. 83 99-

Areas of Advance

Nanoscience and Nanotechnology

Subject Categories

Condensed Matter Physics

DOI

10.1016/j.sse.2013.01.025

More information

Latest update

9/6/2018 2