Biomedical Engineering Reference
In-Depth Information
Chapter 3
Optical Properties of Lateral InGaAs Quantum
Dot Molecules Single- and Bi-Layers
Songphol Kanjanachuchai, Nirat Patanasemakul, Natapong Thongkamkoon,
Nitidet Thudsalingkarnsakul, Naparat Siripitakchai, Pornchai Changmoang,
Supachok Thainoi, and Somsak Panyakeow
Abstract Growth of InGaAs nanostructures by molecular beam epitaxy using
partial-cap and regrowth technique results in an ensemble of lateral quantum dot
molecules (QDMs). Each QDM comprises a large, central quantum dot and several
small, satellite quantum dots which emit at different energies and exhibit qualita-
tively different optical behaviors. This chapter reviews, explains, and discusses the
various fundamental aspects of lateral QDM single layers: the nucleation mecha-
nism, the photoluminescent spectra, and the unique bimodal optical characteristics.
The chapter ends by demonstrating the usefulness of lateral QDM bi-layers as a
promising broadband near-infrared material.
3.1
Introduction
Semiconductor quantum dots (QDs) have been intensively investigated for several
decades since early pioneering work show them to be of high crystalline quality,
capable of optical emission in the near-infrared region [ 1 ]. They are usually grown
by metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy
(MBE) with elemental solid sources or compound gas sources. The standard route
S. Kanjanachuchai ( ) ￿ N. Patanasemakul ￿ N. Thudsalingkarnsakul ￿ N. Siripitakchai
P. Changmoang ￿ S. Thainoi ￿ S. Panyakeow
Semiconductor Device Research Laboratory, Department of Electrical Engineering,
Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
e-mail: songphol.k@chula.ac.th ; nirat.pat@gmail.com ; smearsand@hotmail.com ;
s.naparat@gmail.com ; pornchai.c@chula.ac.th ; Supachok.t@chula.ac.th ;
s panyakeow@yahoo.com
N. Thongkamkoon
International School of Engineering, Faculty of Engineering, Chulalongkorn University,
Bangkok 10330, Thailand
e-mail: ixohoxi 35847@hotmail.com
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