Journal of Crystal Growth 227–228 (2001) 1010–1015 InAs/GaAs self-organized quantum dots on (4 1 1)A GaAs by molecular beam epitaxy S. Kiravittaya*, R. Songmuang, P. Changmuang, S. Sopitpan, S. Ratanathammaphan, M. Sawadsaringkarn, S. Panyakeow Semiconductor Device Research Laboratory, Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand Abstract Self-organized InAs QDs formation on (4 1 1)A GaAs and on controlled (1 0 0) GaAs substrates were studied by in- situ RHEED observation, AFM measurement and PL spectroscopy. The transition from two-dimensional to three- dimensional growth on (4 1 1)A was observed by RHEED pattern transformation to indicate the critical layer thickness of InAs QDs formation. The result is almost the same as that on (1 0 0). Improvement of QDs alignment having dot size uniformity on (4 1 1)A was observed by AFM measurement. Enhanced optical properties of QDs on (4 1 1)A was shown by low-temperature PL spectroscopy. Strong PL peak at 966 nm having FWHM of 35 nm was obtained from the 3- stacked QDs on (4 1 1)A. The narrower PL FWHM of QDs peak on (4 1 1)A comes from the improved uniformity of QDs on (411)A. # 2001 Elsevier Science B.V. All rights reserved. PACS: 64.60.Lx; 81.15.Hi Keywords: A1. Low dimensional structures; A1. Nanostructures; A1. Surface structure; A3. Molecular beam epitaxy; A3. Selective epitaxy 1. Introduction The realization of defect free, high uniformity, self-organized quantum dots (QDs) on semicon- ductor surface by Stranski–Krastanov (SK) growth mode has been achieved [1]. This lead to the possibility to study the (electronic and optical) properties of QDs semiconductor nanostructure which is unique and different from other nano- structures [2]. For this reason, applications in novel devices such as QD laser has been realized [3]. However, most of the self-organized InAs QDs preparation have been conducted on conventional (1 0 0) GaAs substrate, by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposi- tion (MOCVD) techniques. One way to improve or adjust the QDs properties is the utilization of high-index substrates which exhibit some interest- ing phenomena. To date, there are several reports about successful growth of self-organized QDs on high-index substrates, comparable to those with (1 0 0) orientation. Xu et al. reported two-dimen- sional ordering of InGaAs QDs on GaAs (3 1 1)B surface [4]. Nishi et al. showed the improved *Corresponding author. Tel.: +662-218-6524; fax: +662- 251-8991. E-mail address: d1wit@ee.eng.chula.ac.th (S. Kiravittaya). 0022-0248/01/$ - see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0022-0248(01)00978-2