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Full-Text Articles in Condensed Matter Physics
Visible Luminescence From Single Crystal‐Silicon Quantum Wells, Peter N. Saeta, A. C. Gallagher
Visible Luminescence From Single Crystal‐Silicon Quantum Wells, Peter N. Saeta, A. C. Gallagher
All HMC Faculty Publications and Research
Single crystal‐silicon quantum wells with SiO2 barriers have been grown from SIMOX silicon‐on‐insulator substrates. Photoluminescence in the red and near‐infrared is observed for average well width <8 >nm, with peak signal for 2‐nm average width. The luminescence spectrum is independent of well width for SiO2 barriers, but shifts 0.3 eV to higher energy upon removal of the upper oxide layer with HF. Both results suggest the importance of radiation from surface states.
Characterization Of Piezoceramic Crosses With Large Range Scanning Capability And Applications For Low Temperature Scanning Tunneling Microscopy, J. A. Helfrich, Shireen Adenwalla, J. B. Ketterson, G. A. Zhitomirsky
Characterization Of Piezoceramic Crosses With Large Range Scanning Capability And Applications For Low Temperature Scanning Tunneling Microscopy, J. A. Helfrich, Shireen Adenwalla, J. B. Ketterson, G. A. Zhitomirsky
Shireen Adenwalla Papers
We have developed a large amplitude piezoceramic scanner which should have numerous applications. Scanning tunneling microscopy (STM) and other scanning probe microscopies predominantly use piezoceramics for the scanning elements. Similarly adaptive optics, high resolution lithography, and micromanipulators are other examples of research which regularly utilize piezoceramic scanners. We present a new geometry for a piezoceramic scanner which allows for both high resolution (~nanometers) and large amplitude (~400 µm) displacements. The cross-shaped geometry makes it possible to produce extremely long pieces with very high tolerances. We have shown its effectiveness by using it as the major component of a low temperature …
Scanning-Tunneling-Microscopy Study Of Pb On Si(111), D. Tang, H. E. Elsayed-Ali, J. Wendelken, J. Xu
Scanning-Tunneling-Microscopy Study Of Pb On Si(111), D. Tang, H. E. Elsayed-Ali, J. Wendelken, J. Xu
Electrical & Computer Engineering Faculty Publications
Scanning-tunneling microscopy has been used to study temperature and coverage dependence of the structure of lead on the Si(111)-7×7 surface. For low Pb coverage, the Pb atoms favored the faulted sites. The ratio between the number of Pb atoms on faulted to unfaulted sites increased after sample annealing. An energy difference of 0.05 eV associated with a Pb atom on these two sites is estimated. The mobility of Pb atoms on Si(111) was observed at a temperature as low as 260°C for a coverage of 0.1 and 1 ML. © 1995 The American Physical Society.
Nonequilibrium Dynamic Conductivity Of Superconductors: An Exploitable Basis For High Energy Resolution X-Ray Detectors, Armen Gulian, D. Van Vechten
Nonequilibrium Dynamic Conductivity Of Superconductors: An Exploitable Basis For High Energy Resolution X-Ray Detectors, Armen Gulian, D. Van Vechten
Mathematics, Physics, and Computer Science Faculty Articles and Research
A new design for high‐energy radiation/particle detectors is presented. The nonequilibrium response of a superconductor to the absorption of the incident quanta is sensed by electromagnetic measurements of the altered dynamic conductivity. Microwave absorption may be used to amplify the signal. Such a detector will provide better energy resolution than semiconducting charge‐collection devices once the statistical resolution limit is reached.