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107 results on '"Wang, P.D."'

2. Shear strains in dry etched GaAs/A1As wires studied by high resolution x-ray reciprocal space mapping

Author

Darhuber, A.A., Bauer, G., Wang, P.D., and Sotomayor Torres, C.M.

Subjects
X-ray microanalysis -- Usage, Shear (Mechanics) -- Research, Strains and stresses -- Research, Physics
Abstract

Researchers investigated shear strain in quantum wires and quantum dots using high-resolution x-ray reciprocal space mapping technology. This technique is very useful for the investigation of shear strain distribution in semiconductor nanostructures, due to the fact that shear strains affect the intensity of usually weak x-ray diffraction peaks. The researchers were able to detect pitch variations as small as 10% of the period and to demonstrate a discretization pattern.

Published
1998

5. Multiple-phonon relaxation in GaAs-AlGaAs quantum well dots

Author

Wang, P.D. and Torres, C.M. Sotomayor

Subjects
Phonons -- Research, Gallium arsenide -- Research, Gallium arsenide semiconductors -- Research, Quantum wells -- Research, Physics
Abstract

Resonant Raman scattering and hot exciton luminescence from dry etched GaAs-AlGaAs quantum dots in which quantum confinement effects are directly proportional to dot size, are studied. The photoluminescence (PL) and PL excitation in quantum dots exhibit fourth-order multiphonon processes in the quantum dots. Presence of bottleneck effect is indicated by the results.

Published
1993

6. Raman scattering of coupled longitudinal optical phonon-plasmon modes in dryetched n+-GaAs._

Author

Wang, P.D., Foad, M.A., Sotomayor-Torres, C.M., Thoms, S., Watt, M., Cheung, R., Wilkinson, C.D.W., and Beaumont, S.P.

Subjects
Raman effect -- Usage, Semiconductors -- Etching, Gallium arsenide semiconductors -- Research, Physics
Abstract

The damage caused by dry etching on GaAs was studied using Raman scattering wherein the heavily doped n+-GaAs (2-3 to the 18th power super -3) analyzes thedry etch-induced damage through the coupled longitudinal optical phonon-plasmonmode as a probe. Conventional radio frequency etching, ion beam etching and electron cyclotron radio frequency reactive ion etching (ECR-RIE) were used andresults show that ECR-RIE produces the least damage.

Published
1992

7. List of Contributors

Author

Altshuler, B., primary, Arney, S.C., additional, Ashoori, R.C., additional, Averin, D.V., additional, Baldwin, K.W., additional, Barbier, E., additional, Bauer, S., additional, Beaumont, S.P., additional, Beenakker, C.W.J., additional, Behringer, R.E., additional, Benisty, H., additional, Berger, S.D., additional, Bhat, R., additional, Bigelow, N.P., additional, Böhm, G., additional, Bouchard, A.M., additional, Bryant, G.W., additional, Camarda, R.M., additional, Caro, J., additional, Chakraborty, T., additional, Chin, A., additional, Christen, J., additional, Colas, E., additional, Cullis, A.G., additional, Cunningham, J.E., additional, Datta, S., additional, deGraaf, C., additional, de Lozanne, P.G.N., additional, de Vegvar, A.L., additional, Demeester, P., additional, Demel, T., additional, Demmerle, W., additional, Eaves, L., additional, Ehrichs, E.E., additional, Eisenstein, J.P., additional, Farrow, R.C., additional, Ferry, D.K., additional, Foad, M.A., additional, Fowler, A.B., additional, Foxman, E.B., additional, Foxon, C.T., additional, Frost, J.E.F., additional, Fulton, T.A., additional, Gebhardt, W., additional, Gibson, J.M., additional, Goldman, V.J., additional, Goodnick, S.M., additional, Gornik, E., additional, Grambow, P., additional, Grubin, H.L., additional, Halonen, V., additional, Harmans, C.J.P.M., additional, Hasslacher, B., additional, Haviland, D.B., additional, Hayes, D.G., additional, Heitmann, D., additional, Henini, M., additional, Hess, K., additional, Heyers, K., additional, Higgs, A.W., additional, Hirayama, Y., additional, Hirler, F., additional, Hong, J.M., additional, Horikoshi, Y., additional, Huggins, H.A., additional, Hughes, O.H., additional, Hwang, D.M., additional, Iafrate, G.J., additional, Imry, Y., additional, Johnson, A.T., additional, Jones, G.A.C., additional, Kapon, E., additional, Kastner, M.A., additional, Kelly, M.J., additional, Kern, K., additional, Kim, K.W., additional, Kirk, W.P., additional, Kouwenhoven, L.P., additional, Kraus, J.S., additional, Kriman, A.M., additional, Kuhn, W., additional, Kumar, A., additional, Kuzmin, L.S., additional, Lake, R., additional, Law, V.J., additional, Leiderer, H., additional, Leitch, W.E., additional, Lent, C.S., additional, Lévy, L.P., additional, Liddle, J.A., additional, Likharev, K.K., additional, Littlejohn, M.A., additional, Lootens, D., additional, Luscombe, J.H., additional, Ma, J., additional, Mabesoone, M., additional, MacDonald, L., additional, Martin-Moreno, N.C., additional, McEuen, P.L., additional, Meirav, U., additional, Menschig, A., additional, Mickevicius, R., additional, Mitin, V.V., additional, Mooij, J.E., additional, Niu, Q., additional, Palm, E.C., additional, Paris, E., additional, Pease, M., additional, Pepper, R.F., additional, Pfeiffer, L.N., additional, Ploog, K., additional, Popovíc, D., additional, Prentiss, M.G., additional, Radelaar, S., additional, Randall, J.N., additional, Razeghi, M., additional, Reed, M.A., additional, Register, L.F., additional, Ritchie, D.A., additional, Roukes, M.L., additional, Saku, T., additional, Schiavone, L.M., additional, Seabaugh, A.C., additional, Silsbee, R.H., additional, Simmonds, P.E., additional, Sivan, U., additional, Skolnick, M.S., additional, Smart, A.P., additional, Smith, G.W., additional, Smith, W.F., additional, Smoliner, J., additional, Sols, F., additional, Sotomayor-Torrés, C.M., additional, Spector, J., additional, Stanley, C.R., additional, Staring, A.A.M., additional, Stormer, H.L., additional, Stroscio, M.A., additional, Su, S., additional, Tarucha, S., additional, Tewordt, M., additional, Thoms, S., additional, Timmering, C.E., additional, Timp, G., additional, Tokura, Y., additional, Umbach, C.P., additional, Van Daele, P., additional, van der Vaart, N.C., additional, van Houten, H., additional, Wagner, P.H., additional, Wallace, H., additional, Wang, P.D., additional, Washburn, S., additional, Watt, M., additional, Weimann, G., additional, Weisbuch, C., additional, Weiss, D., additional, Weisshaar, A., additional, West, K.W., additional, White, C.R.H., additional, Whitehouse, C.R., additional, Wilkinson, C.D.W., additional, Williams, G.M., additional, Williamson, J.G., additional, Wind, S.J., additional, Wu, J.C., additional, Wybourne, M.N., additional, Yacoby, A,, additional, Yao, J.J., additional, Yindeepol, W., additional, and Zhang, Y.H., additional

Published
1992
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8. GaAs micrometer-sized dot imaging by Raman microscopy

Author

Wang, P.D., Cheng, C., Torres, C.M. Sotomayor, and Batchelder, D.N.

Subjects
Etching -- Methods, Raman spectroscopy -- Usage, Gallium arsenide semiconductors -- Research, Physics
Abstract

Raman microscopy studies of one-micron diameter GaAs semiconductor dot array structures are conducted to assess uniformity and damage to the structures. The samples are produced using electron beam lithography and reactive ion etching, and the properties studied include surface strain mapping, crystal orientation and ion-implant induced damages. Spatial resolution of the image is easily characterized by Raman microscopy since the dot diameter of one micron and the presence of the band pass filter remove disturbance completely.

Published
1993

10. Determination of the strain status of GaAs/AlAs quantum wires and quantum dots

Author

Darhuber, A.A., Bauer, G., Wang, P.D., Song, Y.P., Sotomayor Torres, C.M., Holland, M.C., and Drzal, L.T.

Subjects
Materials science, business.industry, Quantum wire, Quantum point contact, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Computer Science::Other, Reciprocal lattice, Lattice constant, Quantum dot, Optoelectronics, Reactive-ion etching, business, Quantum, Electron-beam lithography
Abstract

We have investigated periodic arrays of 150 and 175 nm wide GaAs-AlAs quantum wires and quantum dots, fabricated by electron beam lithography and SiCI4/O2 reactive ion etching, by means of reciprocal space mapping using triple axis x-ray diffractometry (TAD). The reciprocal space maps reveal that after the fabrication process the lattice constant along the growth direction slightly increases for the wires and even more so for the dots.

Published
1995

11. Elastic relaxation of dry-etched Si/SiGe quantum dots

Author

Darhuber, A.A., Grill, T., Stangl, J., Bauer, G., Lockwood, D.J., Noël, J.-P., Wang, P.D., Sotomayor Torres, C.M., Darhuber, A.A., Grill, T., Stangl, J., Bauer, G., Lockwood, D.J., Noël, J.-P., Wang, P.D., and Sotomayor Torres, C.M.

Abstract

Elastic relaxation of the compressive strain due to the lattice mismatch between SiGe and Si has been studied with both x-ray diffraction and Raman scattering in small (30–100 nm) dry-etched Si/SiGe quantum dots fabricated from high-quality multilayers grown on (001)-oriented Si. The Raman spectroscopic investigations showed that the dot alloy layers have relaxed by approximately 65% from their fully strained value and that a compensating tensile strain has been induced in the Si layers. The relaxation is essentially independent of the dot size and the values derived experimentally compare well with analytical and numerical model calculations.

Published
1998

14. Elastic strains in GaAs/AIAs quantum dots studied by high-resolution x-ray diffraction

Author

Holy, V., Darhuber, A.A., Bauer, G., Wang, P.D., Song, Y.P., Sotomayor Torres, C.M., Holland, M.C., Holy, V., Darhuber, A.A., Bauer, G., Wang, P.D., Song, Y.P., Sotomayor Torres, C.M., and Holland, M.C.

Abstract

We have studied a GaAs/AlAs periodic quantum dot array (fabricated by electron beam lithography and reactive ion etching) using high-resolution x-ray reciprocal space mapping around the (004) and (1¯ 1¯3) reciprocal lattice points. Both the coherently and the diffusely scattered x-ray intensities were analyzed by performing two-dimensional model calculations and comparing them with the measured reciprocal space maps of the diffracted intensity. From the distribution of the diffracted intensities we deduced the average strain status in the dots. From the numerical simulations it is evident that random elastic strain fields are present, which extend through almost the whole volume of the quantum dot. The simulations of the x-ray measurements revealed that the crystalline part of the dots is considerably smaller as scanning electron micrographs would indicate, namely, 50 nm instead of 65 nm, respectively.

Published
1995

15. X-ray reciprocal space mapping of GaAs.AIAs quantum wires and quantum dots

Author

Darhuber, A.A., Koppensteiner, E., Bauer, G., Wang, P.D., Song, Y.P., Sotomayor Torres, C.M., Holland, M.C., Darhuber, A.A., Koppensteiner, E., Bauer, G., Wang, P.D., Song, Y.P., Sotomayor Torres, C.M., and Holland, M.C.

Abstract

Periodic arrays of 150 and 175 nm-wide GaAs–AlAs quantum wires and quantum dots were investigated, fabricated by electron beam lithography, and SiCl4/O2 reactive ion etching, by means of reciprocal space mapping using triple axis x-ray diffractometry. From the x-ray data the lateral periodicity of wires and dots, and the etch depth are extracted. The reciprocal space maps reveal that after the fabrication process the lattice constant along the growth direction slightly increases for the wires and even more so for the dots.

Published
1995

16. Optical emission and Raman scattering in modulation-doped gaAs-AlGaAs quantum wires and dots

Author

Wang, P.D., Song, Y.P., Torres, C.M.S., Holland, M.C., Lockwood, D.J., Hawrylak, P., Palacios, J.J., Christianen, P.C.M., Maan, J.C., Perenboom, J.A.A.J., Wang, P.D., Song, Y.P., Torres, C.M.S., Holland, M.C., Lockwood, D.J., Hawrylak, P., Palacios, J.J., Christianen, P.C.M., Maan, J.C., and Perenboom, J.A.A.J.

Abstract

Contains fulltext : 112786.pdf (publisher's version ) (Open Access)

Published
1994

21. Magneto-optical properties of InAs monolayers and InyAl1−yAs self-assembled quantum dots in Ga(Al)As matrices

Author

Wang, P.D., primary, Merz, J.L., additional, Fafard, S., additional, Leon, R., additional, Leonard, D., additional, Medeiros-Ribeiro, G., additional, Oestreich, M., additional, Petroff, P.M., additional, Ledentsov, N.N., additional, Kop'ev, P.S., additional, Ustinov, V.M., additional, Uchida, K., additional, Miura, N., additional, Akiyama, H., additional, Sakaki, H., additional, and Sotomayor Torres, C.M., additional

Published
1996
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26. Optical spectroscopy of self-organized nanoscale hetero-structures involving high-index surfaces

Author

Ledentsov, N.N., primary, Maximov, M.V., additional, Kop'ev, P.S., additional, Ustinov, V.M., additional, Belousov, M.V., additional, Meltser, B.Ya., additional, Ivanov, S.V., additional, Shchukin, V.A., additional, Alferov, Zh.I., additional, Grundmann, M., additional, Bimberg, D., additional, Ruvimov, S.S., additional, Richter, W., additional, Werner, P., additional, Gösele, U., additional, Heidenreich, J., additional, Wang, P.D., additional, and Sotomayor Torres, C.M., additional

Published
1995
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38. Bulk GaAs ionization detectors for WIMP searches

Author

Spooner, N.J.C., primary, Bewick, A., additional, Holmes, S.N., additional, Phillips, C.C., additional, Quenby, J.J., additional, Stradling, R.A., additional, Summer, T.J., additional, Thomas, R.H., additional, and Wang, P.D., additional

Published
1991
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43. Radiative recombination in GaAs-Al[sub x]Ga[sub 1-x]As quantum dots.

Author

Wang, P.D. and Torres, C.M. Sotomayor

Subjects
*LUMINESCENCE, *LOW temperatures, *QUANTUM dots, *MEASUREMENT
Abstract

Investigates the low-temperature luminescence intensity of dry-etched gallium arsenide-Al[sub x]Ga[sub 1-x]As quantum dots. Decrease of the luminescence intensity; Fabrication of a semiconductor quantum wire laser; Use of time-resolved photoluminescence spectroscopy.

Published
1992
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44. Optical characterization of submonolayer and monolayer InAs structures grown in a GaAs matrix on....

Author

Wang, P.D. and Ledentsov, N.N.

Subjects
*OPTICAL properties, *HETEROSTRUCTURES, *INDIUM compounds, *GALLIUM arsenide
Abstract

Examines the optical properties of indium arsenide/gallium arsenide (InAs/GaAs) heterostructures with indium arsenide average layer thickness. Observation of high optical quality structures of indium arsenide; Attribution of the InAs growth improvement to GaAs surface; Exhibition of improved luminescence efficiency at room temperature.

Published
1994
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45. Exciton dynamics in ultrathin InAs/GaAs quantum-wells

Author

Brübach, J., Haverkort, J.E.M., Wolter, J.H., Wang, P.D., Ledentsov, N.N., Sotomayor Torres, C.M., Pang, S.W., Applied Physics, and Photonics and Semiconductor Nanophysics

Subjects
Materials science, Photoluminescence, Condensed Matter::Other, Phonon, Exciton, Resonance, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Molecular physics, Condensed Matter::Materials Science, symbols.namesake, Excited state, symbols, Emission spectrum, Raman scattering, Excitation
Abstract

We have studied the transient behaviour of a sharp emission line, which emerges close to the heavy-hole (hh) exciton photoluminescence line in a 1.6 monolayer thick InAs layer embedded in a GaAs matrix, when the light-hole (lh) exciton transition is excited. We find, that the decaytime of the sharp line is equal to the lh-exciton lifetime for excitation on resonance, but it strongly decreases for excitation off resonance. Since in our structure the energy separation between the hhand lh-exciton transitions amount to one GaAs LO phonon we conclude, that the sharp line originates from double resonant Raman scattering for off resonant excitation, whereas it is predominantly due to resonant luminescence for excitation on resonance. The strong decrease of the intensity of the sharp line due to a temperature rise from 4 to 18K proves the existence of a well confined lh-exciton state. In addition, we performed carrier capture measurements on this structure. We find a constant capture time of 20ps at the lh-exciton transition, whereas the capture time decreases step-like from 55ps to 22ps within the hh-exciton transition. This provides clear evidence for a two-step capture process, where the lh-level acts as an intermediate capture state.

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