Self-assembled lateral Bi-quantum-dot molecule formation by gas-source molecular beam epitaxy

• Published in: Journal of crystal growth 2007-04, Vol.301, p.735-739
• Main Authors: Suraprapapich, S., Shen, Y.M., Odnoblyudov, V.A., Fainman, Y., Panyakeow, S., Tu, C.W.
• Format: Article
• Language: English
• Subjects: A1. Bi-quantum-dot molecule; A3. Gas-source molecular beam epitaxy; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from vapor; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Quantum dots; Self-assembly
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2006.11.120

Self-assembled InAs bi-quantum-dot molecules (BQDMs) on GaAs (0 0 1) have been achieved using gas-source molecular beam epitaxy (GSMBE) and characterized by atomic force microscopy (AFM) and photoluminescence (PL) measurements. After the initial InAs quantum dots are partially capped with GaAs and followed by deposition of InAs, BQDMs are formed. Photoluminescence spectra of BQDMs can be described by two Gaussian-fitted curves at low temperature due to two different dot sizes. This is consistent with dot height histograms obtained from AFM images of BQDMs. For PL intensity, thermal quenching is observed at temperatures above 100 K. The activation energy of BQDM PL corresponds to nonradiative recombination due to defected-related states and potential fluctuation.