Structural and electrooptical characteristics of quantum dots emitting at 1.3 mum on gallium arsenide

• Published in: IEEE journal of quantum electronics Vol. 37; no. 8; pp. 1050 - 1058
• Main Authors: Fiore, A, Oesterle, U, Stanley, R P, Houdre, R, Lelarge, F, Ilegems, M, Borri, P, Langbein, W, Birkedal, D, Hvam, J M, Cantoni, M, Bobard, F
• Format: Journal Article
• Language: English
• Published: 01-08-2001
• ISSN: 0018-9197
• DOI: 10.1109/3.937394

We present a comprehensive study of the structural and emission properties of self-assembled InAs quantum dots emitting at 1.3 mum. The dots are grown by molecular beam epitaxy on gallium arsenide substrates. Room-temperature emission at 1.3 mum is obtained by embedding the dots in an InGaAs layer. Depending on the growth structure, dot densities of 1-6x10(10) cm(-2) are obtained. High dot densities are associated with large inhomogeneous broadenings, while narrow photoluminescence (PL) linewidths are obtained in low-density samples. From time-resolved PL experiments, a long carrier lifetime of {approximately equal to}1.8 ns is measured at room temperature, which confirms the excellent structural quality. A fast PL rise (tau(rise)=10+/-2 ps) is observed at all temperatures, indicating the potential for high-speed modulation. High-efficiency light-emitting diodes (LEDs) based on these dots are demonstrated, with external quantum efficiency of 1% at room temperature. This corresponds to an estimated 13% radiative efficiency. Electroluminescence spectra under high injection allow us to determine the transition energies of excited states in the dots and bidimensional states in the adjacent InGaAs quantum well