Evolution from point defects to arsenic clusters in low-temperature grown GaAs/AlGaAs multiple quantum wells

Optical transient current spectroscopy (OTCS), photoluminescence (PL) spectroscopy and excitonic electroabsorption spectroscopy have been used to investigate the evolution of defects in the low-temperature grown GaAs/AlGaAs multiple quantum well structures during the postgrowth rapid thermal annealing. The sample was grown at 350 degrees C by molecular beam epitaxy on miscut (3.4 degrees off (001) towards (111)A) (001) GaAs substrate. After growth, the sample was subjected to 30s rapid thermal annealing in the range of 500-800 degrees C. It is found that the integrated PL intensity first decreases with the annealing temperature, then gets a minimum at 600 degrees C and finally recovers at higher temperatures. OTCS measurement shows that besides As,, antisites and arsenic clusters, there are several relatively shallower deep levels with excitation energies less than 0.3 eV in the as-grown and 500 degrees C-annealed samples. Above 600 degrees C, OTCS signals from As,, antisites and shallower deep levels become weaker, indicating the decrease of these defects. It is argued that the excess arsenic atoms group together to form arsenic clusters during annealing. (C) 2000 Elsevier Science B.V. All rights reserved.

Influence of (001) vicinal GaAs substrates on the optical properties of defects in low-temperature grown GaAs/AlGaAs multiple quantum wells

Photoluminescence (PL) spectroscopy and carrier lifetime measurement has been used to characterize optical properties of defects in the low-temperature (LT) grown GaAs/AlGaAs multiple quantum well structures. Two sets of samples were grown at 400 degrees C by molecular beam epitaxy on nominal (001) and miscut [4 degrees off (001) towards (111) A] GaAs substrates, respectively. After growth, samples were subjected to 30 s rapid thermal annealing at 600-800 degrees C. It is found that after annealing, two defect-related PL features appear in the samples grown on nominal (001) GaAs substrates, but not in those grown on miscut (001) GaAs substrates. The carrier lifetimes are about 31 and 5 ps in as-grown samples grown on nominal and miscut (001) GaAs substrates, respectively. The different PL spectra and carrier lifetimes in two sets of samples are attributed to different structures of the As-Ga-like defects formed during LT growth. (C) 1999 American Institute of Physics. [S0003-6951(99)00230-2].

分子束外延GaAs-AlGaAs材料

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分子束外延GaAs/AlGaAs高速器件与光电子器件用料

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GaAs/AlGaAs量子阱红外探测器单管及四元线列

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高质量GaAs/AlGaAs二维电子气材料研制及其器件应用

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甚长波GaAs/AlGaAs量子阱红外探测器的研究

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