Biomedical Engineering Reference
In-Depth Information
Chapter 1
Fabrication of Semiconductor Quantum Dot
Molecules: Droplet Epitaxy and Local Oxidation
Nanolithography Techniques
Pablo Alonso-Gonz alez and Javier Martın-S anchez
Abstract
A semiconductor quantum dot molecule (QDM) composed of two
interacting quantum dots (QDs) is the simplest coupled system formed by semicon-
ductor quantum nanostructures. Potentially, a QDM is the ideal building block for
the realization of a quantum computation device. However, the fabrication of QDMs
is far from being a straightforward task, particularly if a precise control of QDs
density, size, or spatial location is required. Recently, an important improvement in
the control of these properties has been achieved by using patterned semiconductor
substrates followed by preferential epitaxial growth. In this chapter we will overview
two of such fabrication methods, which are based on: (1) in situ droplet epitaxy
“nanodrilling” and (2) ex situ local oxidation nanolithography.
Abbreviations
AFM-LAO
Atomic force microscopy local anodic oxidation
ALMBE
Atomic layer molecular beam epitaxy
BEP
Beam equivalent pressure
CCD
Charge coupled device
MBE
Molecular beam epitaxy
ML
Monolayer
MSM
Metal-semiconductor-metal
PL
Photoluminescence
QD
Quantum dot
QDM
Quantum dot molecule
P. Alonso-Gonzalez (
)J.Martın-Sanchez
Instituto de Microelectronica de Madrid (CNM-CSIC), Isaac Newton 8 (PTM),
28760 Tres Cantos, Madrid, Spain
