| 1. |
- Lipoglavsek, M., et al.
(författare)
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First Observation of Excitation Across the 100Sn Core
- 2001
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Ingår i: Nuclear Physics, Section A. - 0375-9474. ; 682, s. 399-403
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Tidskriftsartikel (refereegranskat)abstract
- Excited states of nuclei near the doubly-magic nucleus Sn-100 were studied with the Ni-58+Cr-50 reaction. The experimental setup consisted of the GAMMASPHERE array augmented with light charged-particle and neutron detectors. Excited states were identified for the first time in the proton emitting nucleus Sb-105. Excitations across the N=Z=50 doubly closed shell were observed in Cd-99 and In-101. Some results of large-scale shell-model calculations are discussed.
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| 2. |
- Paul, D.J., et al.
(författare)
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n-type Si/SiGe resonant tunnelling diodes
- 2002
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Ingår i: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 89:1-3, s. 26-29
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Resonant tunnelling diodes (RTDs) have been fabricated using Si/SiGe heterolayers which demonstrate room temperature performance comparable to III-V technology. Peak current densities up to 282 kA cm-2 with peak-to-valley current ratios (PVCRs) of 2.4 have been demonstrated at room temperature in devices with dimensions of 5 × 5 µm2. Scaling the device size demonstrates that the peak current density is inversely proportional to the device area. It is suggested that this is related to thermal limitations in the device structure. Estimates are also produced for the maximum frequency of oscillations of the diodes which suggest that oscillators may operate with speeds comparable to III-V diodes. © 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Paul, D.J., et al.
(författare)
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Si/SiGe electron resonant tunneling diodes with graded spacer wells
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 78:26, s. 4184-4186
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Tidskriftsartikel (refereegranskat)abstract
- Resonant tunneling diodes have been fabricated using graded Si1 - xGex (x = 0.3?0.0) spacer wells and strained Si0.4Ge0.6 barriers on a relaxed Si0.7Ge0.3 n-type substrate which demonstrates negative differential resistance at up to 100 K. This design is aimed at reducing the voltage at which the peak current density is achieved. Peak current densities of 0.08 A/cm2 with peak-to-valley current ratios of 1.67 have been achieved for a low peak voltage of 40 mV at 77 K. This represents an improvement of over an order of magnitude compared to previous work. © 2001 American Institute of Physics.
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| 4. |
- Pfohl, J., et al.
(författare)
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Highly deformed rotational structures in 136Pm
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:3, s. 313041-313045
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Tidskriftsartikel (refereegranskat)abstract
- Four highly deformed structures in the odd-odd nucleus 13661Pm75 were observed via the 105Pd(35Cl,2p2n) reaction at 180 and 173 MeV using the GAMMASPHERE γ-ray spectrometer and the Microball charged-particle detector array. Quadrupole moment measurements were performed on all of the bands. In contrast to lighter odd-Ζ Pm and Pr nuclei, bands based on the g9/2[404]9/2 proton orbital were not observed. Instead, the four observed sequences are assigned as a coupling of an i13/2 neutron with the low-Ω h11/2 and mixed d5/2g7/2 orbitals. Comparisons with neighboring highly deformed structures are discussed and cranked Nilsson-Strutinsky calculations for 136Pm are presented.
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| 5. |
- See, P., et al.
(författare)
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High performance Si/Si1-x Gex resonant tunneling diodes
- 2001
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 22:4, s. 182-184
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Tidskriftsartikel (refereegranskat)abstract
- Resonant tunneling diodes (RTDs) with strained i-Si0.4 Ge06. potential barriers and a strained i-Si quantum well, all on a relaxed Si0.8 Ge0.2 virtual substrate were successfully grown by ultra high vacuum compatible chemical vapor deposition and fabricated using standard Si processing methods. A large peak to valley current ratio of 2.9 and a peak current density of 4.3 kA/cm2 at room temperature were recorded from pulsed and continuous dc current-voltage measurements, the highest reported values to date for Si/Si1-x Gex RTDs. These dc figures of merit and material system render such structures suitable and highly compatible with present high speed and low power Si/Si1-x Gex heterojunction field effect transistor based integrated circuits.
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| 6. |
- Wilson, A. N., et al.
(författare)
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Magnetic dipole bands in 190Hg : First evidence of excitations across the Z = 82 sub-shell in Hg nuclei
- 2001
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 505:1-4, s. 6-14
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Tidskriftsartikel (refereegranskat)abstract
- An experiment aimed at studying high-spin states in 190Hg was performed with the Eurogam II array. The data have revealed the presence of cascades of magnetic dipole transitions with some unexpected properties. Unlike the MI bands previously observed in the heavier Hg isotopes, these structures have extremely large B(M1)/B(E2) ratios, The observation of a third dipole band with much lower B(M1)/B(E2) values in the same spin/excitation energy regime suggests that the bands may represent configurations occurring in different minima in the potential energy surface. Configuration-dependent Cranked Nilsson-Strutinsky calculations predict the presence of a minimum in the nuclear potential energy surface at a deformation of ε ≅ 0.2, γ ≅ -90°, occurring when a proton is excited across the Z = 82 shell-gap into an h9/2 orbital. It is suggested that the bands exhibiting anomalously large B(M1)/B(E2) ratios may be associated with this minimum.
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