All Physics Faculty Publications

Document Type

Article

Journal/Book Title/Conference

Journal of Applied Physics

Volume

113

Issue

20

Publication Date

2013

DOI

http://dx.doi.org/10.1063/1.4808337

Abstract

Using 800 nm, 25-fs pulses from a mode locked Ti:Al2O3 laser, we have measured the ultrafast optical reflectivity of MBE-grown, single-layer In0.4Ga0.6As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140 fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and annealing temperature. With increasing excited carrier density, the capture rate decreases; this slowing of the dynamics is attributed to Pauli state blocking within the InGaAs quantum layer.

Comments

Published by American Institute of Physics. Publisher PDF available for download through link above.

Included in

Physics Commons

Share

COinS