The effect of spacer layer thickness on vertical alignment of InGaAs/GaNAs quantum dots grown on GaAs(3 1 1)B substrate |
| |
| Institution: | 1. Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan;2. School of Engineering, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan;3. Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan;1. Department of ECE, Sethu Institute of Technology, India;2. Department of ECE, Thiagarajar College of Engineering, India;1. IES, Univ. Montpellier, CNRS, F-34000 Montpellier, France;2. CTM, Univ. Montpellier, F-34000 Montpellier, France;3. C2N, CNRS- Univ. Paris-Sud, Univ. Paris-Saclay, 10 Avenue Thomas Gobert, F-91120 Palaiseau, France;1. State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, PR China;2. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, PR China;1. Instituto de Energía Solar – Universidad Politécnica de Madrid ETSI Telecomunicación, Ciudad Universitaria sn, 28040 Madrid, Spain;2. Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan |
| |
| Abstract: | We fabricated multiple stacked self-organized InGaAs quantum dots (QDs) on GaAs (3 1 1)B substrate by atomic hydrogen-assisted molecular beam epitaxy (H-MBE) to realize an ordered three-dimensional QD array. High quality stacked QDs with good size uniformity were achieved by using strain-compensation growth technique, in which each In0.35Ga0.65As QD layer was embedded by GaNAs strain-compensation layer (SCL). In order to investigate the effect of spacer layer thickness on vertical alignment of InGaAs/GaNAs QDs, the thickness of GaNAs SCL was varied from 40 to 20 nm. We observed that QDs were vertically aligned in 3 1 1] direction when viewed along 0 1 −1], while the alignment was inclined when viewed along −2 3 3] for all samples with different SCL thickness. This is due to their asymmetric shape along −2 3 3] with two different dominant facets thereby the local strain field around QD extends further outward from the lower-angle facet. Furthermore, the inclination angle of vertical alignment QDs became monotonously smaller from 22° to 2° with decreasing SCL thickness from 40 to 20 nm. These results suggest that the strain field extends asymmetrically resulting in vertically tilted alignment of QDs for samples with thick SCLs, while the propagated local strain field is strong enough to generate the nucleation site of QD formation just above lower QD in the sample with thinner SCLs. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
