Showing papers by "Wei Jiang published in 2001"
TL;DR: In this article, the photoluminescence properties of InAs/GaAs self-assembled quantum dots (QDs) by varying excitation power and temperature were investigated. And the authors showed that there exists a bimodal size distribution in the QD ensemble.
Abstract: We study the photoluminescence (PL) properties of InAs/GaAs self-assembled quantum dots (QDs) by varying excitation power and temperature. Excitation power-dependent PL shows that there exists bimodal size distribution in the QD ensemble. Thermal carrier redistribution between the two branches of dots is observed and investigated in terms of the temperature dependence of their relative PL intensity. Based on a model in which carrier transfer between dots is facilitated by the wetting layer, the experimental results are well explained. (C) 2001 American Institute of Physics.
64 citations
TL;DR: In this article, the effect of the elastomer stiffness on brittle-tough transition temperature and the elasticity of elastomers was quantitatively studied and the results indicated that the modulus must be one-tenth or less of that of the matrix in order to be effective at low temperature.
32 citations
TL;DR: In this paper, a new volume-combining rule was used to evaluate the close-packed volume per mer, υ*, of the PMMA/SAN blends and the calculated results showed that the new and the original volumecombining rules had a slight influence on the FH interaction parameter, the enthalpy of the mixing, and the combinatorial entropy of mixing.
Abstract: Polymer blends of poly(methyl methacrylate) (PMMA) and poly(styrene-co-acrylonitrile) (SAN) with an acrylonitrile content of about 30 wt % were prepared by means of solution-casting and characterized by virtue of pressure−volume−temperature (PVT) dilatometry. The Sanchez−Lacombe (SL) lattice fluid theory was used to calculate the spinodals, the binodals, the Flory−Huggins (FH) interaction parameter, the enthalpy of the mixing, the volume change of the mixing, and the combinatorial and vacancy entropies of the mixing for the PMMA/SAN system. A new volume-combining rule was used to evaluate the close-packed volume per mer, υ*, of the PMMA/SAN blends. The calculated results showed that the new and the original volume-combining rules had a slight influence on the FH interaction parameter, the enthalpy of the mixing, and the combinatorial entropy of the mixing. Moreover, the spinodals and the binodals calculated with the SL theory by means of the new volume-combining rule could coincide with the measured data ...
18 citations
TL;DR: In this paper, random telegraph noise in the photoluminescence from InGaAs quantum dots in GaAs has been investigated, and the experiments show that the switching inGaAs dots behave very similarly to switching InP dots in InP, but differently from the more commonly investigated colloidal dots.
Abstract: We have investigated random telegraph noise in the photoluminescence from InGaAs quantum dots in GaAs. Dots switching among two and three levels have been measured. The experiments show that the switching InGaAs dots behave very similarly to switching InP dots in GaInP. but differently from the more commonly investigated colloidal dots. The switching is attributed to defects, and we show that the switching can be used as a monitor of the defect.
13 citations
21 Jul 2001-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: Grazing incident X-ray diffraction at different grazing angles for self-organized Ge dots grown on Si(0,0,1) are carried out and lattice constant expansions of 1.2% parallel to the surface as compared with the Si lattice are found within the Ge dots as discussed by the authors.
Abstract: Grazing incident X-ray diffraction at different grazing angles for self-organized Ge dots grown on Si(0 0 1) are carried out and lattice constant expansions of 1.2% parallel to the surface as compared with the Si lattice are found within the Ge dots. A 3.1% lattice expansion of the Ge dots along the growth direction is also found by ordinary X-ray (0 0 4) diffraction. According to the Poisson equation and the Vegard law, our results infer that the Ge dot should be a partially strain relaxed SiGe alloy with Ge content of about 55%.
4 citations