Controlling Lateral Ordering of InGaAs Quantum Dots with Arsenic Background
- PDF / 795,495 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 98 Downloads / 191 Views
0959-M17-16
Controlling Lateral Ordering of InGaAs Quantum Dots with Arsenic Background Euclydes Marega Jr. 1, Ziad Abu Waar2, Mohammad Hussein2, and Gregory Salamo2 1 FÌsica e CiÍncia dos Materiais, Universidade de S„o Paulo, CP 369, CEP 13560-970, S„o Carlos, 13560-970, Brazil 2 Physics, University of Arkansas, 226 Physics Building, Fayetteville, AR, 72701
ABSTRACT We present in this work a method to control two-dimensional (2D) lateral ordering of In0.4Ga0.6As quantum dots (QDs) using the GaAs surface morphology and growth conditions. We have shown experimentally that the 2D ordering is due to the GaAs surface morphology. By setting the correct growth conditions, such as substrate temperature and Arsenic background, the 2D lateral ordering can be improved by the stacking of In0.4Ga0.6As QDs layers. Our results are consistent with reported in experimental and theoretical studies on surface structure and diffusion mechanism over GaAs surface.
INTRODUCTION Nanostructures have become an important field of study in the past few years for their interesting physical characteristics due to featuresí size and quantum confinement, which have added new potential applications to the scope of electrical and optical devices. Quantum dots in specific have the ability to confine electrons in three dimensions resulting in many advantages over other materials. However, many applications like detectors, low-threshold lasers, photonic crystals, require a high uniformity in size, shape and distribution of QDs in order to prove their advantages. Due to the self-assembly process of forming QDs, inhomogeneous broadening in size and shape has degraded their device properties. Therefore, the need for controlling the size, shape and distribution of QDs has become an important area of research in the recent years. Ordering of QDs has attracted increasing attention because of potential applications in electronics device fabrication and quantum computing (1, 2, 3). However, the nature of the nucleation process of QDs in the strained epitaxial Stranski-Krastanow (SK) growth mode results in a random distribution of QDs. The growth of multilayer structures make possible the fabrication of ordered QD structures (4, 5, 6). But controlling self-assembled lateral arrangement with uniform two-dimensional (2D) lateral distances still remains a difficult task (7, 8). In this work, we proposed a combination of properties to control 2D lateral ordering of In0.4Ga0.6As QDs on a GaAs surface using natural surface anisotropic of (100), surface steps for (n11)B GaAs surfaces, arsenic background and substrate temperature. Ordered QDs with low indium composition on a GaAs (100), (311)B and (511)B was obtained for multilayered structures. Although we observed that the lateral 2D ordering is correlated with the surface morphology. The usage of As2 molecules instead of As4 can be a reasonable way to control the size and the size-distribution of the 2D QDs arrays.
EXPERIMENTAL DETAILS The In0.4Ga0.6As QDs investigated in this work were grown by molecular beam
Data Loading...
