Two sub-band conductivity of Si quantum well

Mika Prunnila; Jouni Ahopelto

doi:10.1016/j.physe.2005.12.093

paper

Two sub-band conductivity of Si quantum well

arXiv:cond-mat/0507416 · doi:10.1016/j.physe.2005.12.093

Abstract

We report on two sub-band transport in double gate SiO $_{2}$ -Si-SiO $_{2}$ quantum well with 14 nm thick Si layer at 270 mK. At symmetric well potential the experimental sub-band spacing changes monotonically from 2.3 to 0.3 meV when the total density is adjusted by gate voltages between $\sim 0.7 \times 1 0^{16}$ $- 3.0 \times 1 0^{16}$ m $^{- 2}$ . The conductivity is mapped in large gate bias window and it shows strong non-monotonic features. At symmetric well potential and high density these features are addressed to sub-band wave function delocalization in the quantization direction and to different disorder of the top and bottom interfaces of the Si well. Close to bi-layer/second sub-band threshold the non-monotonic behavior is interpreted to arise from scattering from localized band tail electrons.

Presented at MSS12 conference July 10-15, 2005 Albuquerque, New Mexico, USA. Post-deadline paper, Poster PA2-293. Version 2: typos corrected, few clarifications added in the text, summary shortened, title removed from Ref. 3