Eur. Phys. J. B 62, 65-70 (2008)
https://doi.org/10.1140/epjb/e2008-00127-8

Electron dynamics in modulation p-doped InGaAs/GaAs quantum dots

¹ Department of Physics, Yunnan University, Kunming, Yunnan, 650091, P.R. China
² Centre for Atom Optics and Ultrafast Spectroscopy, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
³ Department of Electronic Materials and Engineering, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, ACT, 0200, Australia

Corresponding author: ^a xwen@unimelb.edu.au

Received: 7 June 2007
Revised: 28 February 2008
Published online: 28 March 2008

Abstract

We investigate the electron dynamics of p-type modulation doped and undoped InGaAs/GaAs quantum dots using up-conversion photoluminescence at low temperature and room temperature. The rise time of the p-doped sample is significantly shorter than that of the undoped at low temperature. With increasing to room temperature the undoped sample exhibits a decreased rise time whilst that of the doped sample does not change. A relaxation mechanism of electron-hole scattering is proposed in which the doped quantum dots exhibit an enhanced and temperature independent relaxation due to excess built-in holes in the valence band of the quantum dots. In contrast, the rise time of the undoped quantum dots decreases significantly at room temperature due to the large availability of holes in the ground state of the valence band. Furthermore, modulation p-doping results in a shorter lifetime due to the presence of excess defects.