12 February 2001 Physics Letters A 280 (2001) 77–80 www.elsevier.nl/locate/pla Carrier transfer between V-grooved quantum wire and vertical quantum well W. Lu a , X.Q. Liu a , Z.F. Li a , S.C. Shen a , Q.X. Zhao b,∗ , Y. Fu b , M. Willander b , H.H. Tan c , C. Jagadish c , J. Zou d , D.J.H. Cockayne d a National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 420 Yudian Road, Shanghai 200083, China b Microelectronics Center at Chalmers, Physical Electronics and Photonics, Department of Physics, University of Gothenburg and Chalmers University of Technology, Fysikgränd 3, S-412 96 Gothenburg, Sweden c Department of Electronic Material Engineering, Research School of Physical Science and Engineering, The Australian National University, Canberra, ACT 0200, Australia d Electron Microscope Unit and Australian Key Center for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006, Australia Received 10 March 2000; received in revised form 11 May 2000; accepted 2 January 2001 Communicated by A. Lagendijk Abstract We report the temperature dependence of the photoluminescence from our V-grooved GaAs/AlGaAs quantum wires. Based on the specially resolved luminescence results, our results show that in the processes of real space carrier transfer from the vertical quantum well region to quantum wire region, a 3.5 meV thermal activation energy has been experimentally observed in our sample. The thermal activation is attributed as the scattering process of carriers from two-dimensional states in the vertical quantum well to the one-dimensional quantum wire states. Based on numerical energy band structure analysis, a thermal activation energy of 2–9 meV is obtained theoretically, in good agreement with the experimental data.  2001 Elsevier Science B.V. All rights reserved. PACS: 78.66.Fd; 73.61.Ey; 71.35.-y; 71.55.Eq; 72.15.Rn The great success of electron and hole confine- ments in two-dimensional (2D) quantum well sys- tems [1,2] excites further interest in the even-lower- dimensional systems, i.e., quasi-one-dimensional (1D) [3,4] and quasi-zero-dimensional (0D) semiconduc- tor structures [5]. In comparison with the bulk (three- dimensional, 3D) and 2D semiconductors, the quan- * Corresponding author. E-mail address: zhao@fy.chalmers.se (Q.X. Zhao). tum wire (QWR) system exhibits stronger oscillations at the energy bandedges in its density of states. And its reduced density of states due to extra one-dimensional quantum confinement as compared with 2D quantum well results in a population inversion at a lower thresh- old current. Recently, low-threshold GaAs QWR laser has been demonstrated by Kapon [3] and Tiwari [6] using epitaxial growth on V-grooved substrate. Because of the small active volume in QWR device, a highly efficient process of carrier trapping into the QWR region becomes crucial for laser operation [7]. 0375-9601/01/$ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII:S0375-9601(01)00022-6