Tunnel-injection lasers promise various advantages in comparison to conventional laser designs. In this paper, the physics of the tunnel injection process is studied within a microscopic theory in order to clarify design requirements for laser structures based on quantum dots as active material and an injector quantum well providing excited charge carriers. We analyze how the electronic states of the injector quantum well and quantum dot levels should be aligned and in which way their coupling through the tunnel-injection barrier should be adjusted for optimal carrier injection rates into the quantum-dot ground state used for the laser transition. Our description of the tunnel-injection process combines two main ingredients: the tunnel coupling of the wave functions as well as the phonon-and Coulomb-assisted transition rates. For this purpose, material-realistic electronic state calculations for the coupled system of injector quantum well, tunnel barrier, and quantum dots are combined with a many-body theory for the carrier scattering processes. We find that the often assumed longitudinal-optical-phonon resonance condition for the level alignment has practically no influence on the injection rate of carriers into the quantum dot states. The structural design should provide optimal hybridization of the injector quantum well states with excited quantum dot states.
Tunnel-injection lasers promise advantages in modulation bandwidth and temperature stability in comparison to conventional laser designs. In this paper, we present results of a microscopic theory for laser properties of tunnel-injection devices and a comparison to a conventional quantumdot laser structure. In general, the modulation bandwidth of semiconductor lasers is affected by the steady-state occupations of electrons and holes via the presence of spectral hole burning. For tunnel-injection lasers with InGaAs quantum dot emitting at the telecom wavelength of 1,55µm, we demonstrate that the absence of spectral hole burning favors this concept over conventional quantum-dot based lasers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.