Short-wavelength laser diodes based on AlInAs/AlGaAs self-assembled quantum dots

Autor:	S. Fafard, Yan Feng, E. M. Griswold, Karin Hinzer, J. Lapointe, A. Delâge, Anthony J. SpringThorpe
Rok vydání:	2000
Předmět:	Materials science business.industry General Physics and Astronomy Heterojunction Semiconductor laser theory Gallium arsenide chemistry.chemical_compound chemistry Quantum dot Optoelectronics Stimulated emission business Lasing threshold Wetting layer Molecular beam epitaxy
Zdroj:	Journal of Applied Physics. 87:1496-1502
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.372040
Popis:	Self-assembled quantum dots (QDs) of highly strained InAlAs have been grown by molecular beam epitaxy in separate-confinement p–i–n heterostructures on (001) GaAs substrates. Results from a systematic study of samples with varying amounts of deposited material relates the observed emission peaks with QD levels, wetting layer states, or barrier materials. For samples with high-QD concentration, lasing is observed in the upper-QD shells. A sample with contact layers improving carrier and optical confinement operates up to room temperature and displays lowered threshold current densities. A threshold current density of ∼4 A/cm2 is measured for this structure at T=5 K and continuous-wave operation is obtained up to T∼77 K. A material gain larger than 1.7×104 cm−1 is measured for this single-layer structure. Lasing is observed in the upper-QD shells for small gain media, and progresses towards the QD lower states for longer cavity lengths representing an emission shift of 45 meV. A minor dependence of the thre...
Databáze:	OpenAIRE
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