Journal of Crystal Growth 261 (2004) 38–43 Optical characteristics of self-assembled InAs quantum dots with InGaAs grown by a molecular beam epitaxy Jin Soo Kim a, *,DaeKonOh a ,PhilWonYu b , Jae-Young Leem c ,JooInLee d , Cheul-Ro Lee e a Basic Research Laboratory, Electronics and Telecommunications Research Institute, 161 Gajeong-dong Yuseong-gu, Daejeon 305-350, South Korea b Department of Physics, Wright State University, Dayton, OH 45435, USA c School of Nano Engineering, Institute for Nanotechnology Applications, Inje University, Gimhae, South Korea d Materials Evaluation Center, Korea Research Institute of Standards and Science, Daejeon, South Korea e School of Advanced Materials Engineering, Chonbuk National University, Chonju, South Korea Received 16 August 2003; accepted 10 September 2003 Communicated by M. Schieber Abstract Self-assembled InAs quantum dots (QDs) with In 0.15 Ga 0.85 As were grown by a molecular beam epitaxy and their opticalpropertieswereinvestigatedbyphotoluminescence(PL)spectroscopy.ForInAsQDsinsertedinanasymmetric In 0.15 Ga 0.85 Asquantumwell,theemissionpeakpositionofQDsis1.30 mm(0.953eV)withnarrowerPLlinewidthand largerenergy-levelspacingbetweenthegroundstatesandthefirstexcitedstatescomparedtothoseofQDsembeddedin aGaAsmatrix.WhiletheroomtemperaturePLyieldforInAsQDsinaGaAsmatrixwasreducedby1/99fromthat measured at 18K, the reduction in PL yield for InAs QDs, grown on a 1nm In 0.15 Ga 0.85 As layer, with a 6nm In 0.15 Ga 0.85 Asovergrowthlayerwasonly1/27.Also,usingtheIn 0.15 Ga 0.85 Asovergrowthlayersignificantlyreducedthe temperature sensitivity of the peak energy for InAs QDs. The relatively better temperature PL characteristics of the QDs with In 0.15 Ga 0.85 As, as well as the ability to control the emission peak position and the energy-level spacing are interesting and important for device applications. r 2003 Elsevier B.V. All rights reserved. PACS: 78.66.Fd; 81.05.Ea; 81.15.Hi Keywords: A1. Energy-level control; A1. Strained-reducing layer; A3. Quantum dots 1. Introduction In the past several years, zero-dimensional quantum dot (QD) structure with three-dimen- sional confinement has been attracting strong interests for the potential device applications such as a laser diode and a light emitting diode [1,2], mainlyduetoitsatomic-likejointdensityofstates. As an example, a QD laser diode is expected to have high thermal stability, low threshold current density, and high differential gain. However, the superior device performance has not been ARTICLE IN PRESS *Corresponding author. Tel.: +82-42-860-6021; fax: +82- 42-860-6248. E-mail address: kjinsoo@etri.re.kr (J.S. Kim). 0022-0248/$-see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2003.09.017