InAs-GaAs quantum dots: From growth to lasers
Journal
Physica Status Solidi (B) Basic Research
Journal Volume
194
Journal Issue
1
Pages
159-173
Date Issued
1996
Author(s)
Bimberg D
Ledentsov N.N
Grundmann M
Kirstaedter N
Schmidt O.G
Ustinov V.M
Egorov A.Yu
Zhukov A.E
Kopev P.S
Alferov Zh.I
Ruvimov S.S
Gösele U
Heydenreich J.
Abstract
Injection lasers based on InAs-GaAs and InGaAs-GaAs quantum pyramids (QPs) with a lateral size ranging from 80 to 140 Å are realized. The structures with relatively small dots (≈80 Å) exhibit properties predicted earlier for quantum dot (QD) lasers such as low threshold current densities (below 100 A cm-2) and ultrahigh characteristic temperatures (T0 = 350 to 425K). For temperatures of operation above 100 to 130 K T0 decreases and the threshold current density increases (up to 0.95 to 3.3 kA cm-2 at room temperature) due to carrier evaporation from QPs. Larger InAs QPs (≈140 Å) providing better carrier localization exhibit saturation of the ground state emission and enhanced nonradiative recombination rate at high excitation densities. The radiative lifetime shows a weak dependence on the dot size (80 to 110 Å) being close to ≈1.8 to 2 ns, respectively. A significant decrease in radiative lifetime is realized in vertically-coupled quantum dots formed by a QP shape-transformation effect. The final arrangement represents a three-dimensional tetragonal array of InAs islands inserted in a GaAs matrix each composed of several vertically merging InAs parts. The first injection lasing in such an array is achieved.
SDGs
Type
journal article