Open Access Nano Ideas

Effects of Shape and Strain Distribution of Quantum Dots on Optical Transition in the Quantum Dot Infrared Photodetectors

X-F Yang1*, X-S Chen1, W Lu1* and Y Fu2

Author Affiliations

1 National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yutian Road, 200083, Shanghai, China

2 Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, AlbaNova, Stockholm, 106 91, Sweden

For all author emails, please log on.

Nanoscale Research Letters 2008, 3:534-539  doi:10.1007/s11671-008-9175-8

Published: 21 October 2008

Abstract

We present a systemic theoretical study of the electronic properties of the quantum dots inserted in quantum dot infrared photodetectors (QDIPs). The strain distribution of three different shaped quantum dots (QDs) with a same ratio of the base to the vertical aspect is calculated by using the short-range valence-force-field (VFF) approach. The calculated results show that the hydrostatic strain ɛHvaries little with change of the shape, while the biaxial strain ɛBchanges a lot for different shapes of QDs. The recursion method is used to calculate the energy levels of the bound states in QDs. Compared with the strain, the shape plays a key role in the difference of electronic bound energy levels. The numerical results show that the deference of bound energy levels of lenslike InAs QD matches well with the experimental results. Moreover, the pyramid-shaped QD has the greatest difference from the measured experimental data.

Keywords:
Quantum dots; PL spectrum; Strain; QDIP