Quantum confinement of crystalline silicon nanotubes with nonuniform wall thickness: Implication to modulation doping

Authors

Binghai Yan, Tsinghua University
Xiao Cheng Zeng, University of Nebraska-LincolnFollow
Jian Wu, Tsinghua University
Bing-Lin Gu, Tsinghua University, Beijing 100084, People’s Republic of China
Wenghui Duan, Tsinghua University, Beijing 100084, People’s Republic of China

Date of this Version

September 2007

Comments

Published by American Institute of Physics. Appl. Phys. Lett. 91, 103107 2007 © 2007 American Institute of Physics. Permission to use. http://apl.aip.org/.

Abstract

First-principles calculations of crystalline silicon nanotubes (SiNTs) show that nonuniformity in wall thickness can cause sizable variation in the band gap as well as notable shift in the optical absorption spectrum. A unique quantum confinement behavior is observed: the electronic wave functions of the valence band maximum and conduction band minimum are due mainly to atoms located in the thicker side of the tube wall. This is advantageous to spatially separate the doping impurities from the conducting channel in doped SiNTs. Practically, the performance of the SiNT-based transistors may be substantially improved by selective p/n doping in the thinner side of the tube wall in the spirit of modulation doping.