Surface flattening during MOCVD of thin GaAs layers covering InGaAs quantum dots

• Published in: Journal of crystal growth Vol. 221; no. 1; pp. 581 - 585
• Main Authors: Sellin, R, Heinrichsdorff, F, Ribbat, Ch, Grundmann, M, Pohl, U.W, Bimberg, D
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-12-2000; Elsevier
• Subjects: Annealing; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; InGaAs/GaAs; Laser; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; MOCVD; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum dots; Surface morphology; 61.16.C; Annealing; Quantum dots; InGaAs/GaAs; Surface morphology; Laser; 81.05.D; 81.15.G; 85.30.V; MOCVD; Atomic force microscopy; Gallium arsenides; Inorganic compounds; Semiconductor materials; Photoluminescence; Surfaces; Crystal growth from vapors; Experimental study; Coatings; Indium arsenides; Thin films; Flattening; Morphology; Thermal annealing; Arsenides; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(00)00782-X

Methods to re-establish a flat growth front on top of the corrugated surface of InGaAs quantum dots (QDs) during MOCVD are reported. Overgrowth temperatures at least 100
K higher than the low QD deposition temperature of 490°C are required for a reduction of the corrugation. In order to avoid degradation of the QDs, however, the temperature must not be increased unless the QDs are buried by ∼3
nm GaAs deposited at the QD growth temperature. Application of an additional annealing step after deposition of the GaAs cap layer improves the surface flatness and leads to an improvement of the radiative recombination efficiency. Lasers grown using such an annealing process for GaAs spacers of an InGaAs QD stack show lower threshold currents and higher internal quantum efficiency.