The samples were grown by molecular beam epitaxy (MBE). The sample structures are GaAs cap (6.5 nm) /Al_0.1In_0.9Sb cap (50 nm)/InSb or InAs_0.1Sb_0.9 active layer (L_w)/Al_0.1In_0.9Sb buffer (700 nm)/GaAs (100) substrate. The layer structures are the same except the active layer for both QW structures. The substrate is a semi-insulating GaAs and all layers are undoped. The well width (L_w) of the active layer is 15 ~ 200 nm.

As shown in Fig.1, the resistivity in low temperature of InAs_0.1Sb_0.9 QWs is much smaller than that of InSb QWs. The difference has been found to result from the band alignment calculated for these QW structures. Fig.2 indicates that the bottom of the conduction band of InSb QWs is depleted above the Fermi level (E_F), while that of InAs_0.1Sb_0.9 QWs is just under E_F in low temperature. In addition, the mobility of InSb QWs falls markedly with decreasing L_w, while that of the InAs_0.1Sb_0.9 QWs hardly depends on the well width. The mobility decrease with narrowing L_w could originate from the possible strain-effect due to the lattice mismatch.

This work was partly supported by the Japan Society for the Promotion of Science (JSPS), Grant-in-Aid for Scientific Research (C: 24560034).

Fig.1 Well-width dependence of mobility   Fig.2 Energy-band diagram for Lw =70 nm

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/29477 must be provided.