51. |
Activation field of ferroelectric (Pb,La)(Zr,Ti)O3thin film capacitors |
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Applied Physics Letters,
Volume 71,
Issue 15,
1997,
Page 2211-2213
T. K. Song,
S. Aggarwal,
A. S. Prakash,
B. Yang,
R. Ramesh,
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摘要:
We report results on the activation field and frequency dependence of the coercive voltage in epitaxial ferroelectric thin film capacitors. Frequency dependent hysteresis loops and pulse width dependent polarization of epitaxialLa0.5Sr0.5CoO3/(Pb,La)(Zr,Ti)O3/La0.5Sr0.5CoO3capacitor structures were measured as a function of La content. The coercive voltages and their frequency dependence vary systematically with increasing La content. We show that the activation field for polarization reversal is directly related to thec/aratio (tetragonality ratio) of the ferroelectric layer. A largerc/aratio leads to a larger field to activate the motion of domain walls through the lattice. An important consequence of a larger activation field is a stronger pulse width dependence of the pulse switched polarization. ©1997 American Institute of Physics.
ISSN:0003-6951
DOI:10.1063/1.119383
出版商:AIP
年代:1997
数据来源: AIP
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52. |
Passivation and surface leakage in CdZnTe spectrometers |
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Applied Physics Letters,
Volume 71,
Issue 15,
1997,
Page 2214-2215
A. Ruzin,
Y. Nemirovsky,
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摘要:
The subject of surface leakage and passivation in spectrometers fabricated in high pressure Bridgman CdZnTe crystals with evaporated gold contacts has been examined. The surface leakage has been found to be the dominant mechanism of dark current leakage in metal–semiconductor–metal detectors with noninjecting contacts. Several passivation techniques have been examined with various degrees of success in terms of reducing the mean value and the power spectral density of dark noise characteristics. An insulating polymer was applied on the bare surface reducing the total leakage current by the factor of 6–7, while favorably affecting the dark noise spectral density by decreasing the corner frequency of the low frequency noise. However, a considerable surface leakage has been observed even in these apparently passivated spectrometers. A three terminal device with iso-potential high voltage contacts has been fabricated and tested, exhibiting a reduction of the total dark current leakage by approximately two orders of magnitude. With this three terminal design, the bulk resistivity of typical high pressure Bridgman crystals is correctly determined and found to be∼2⋅1011 &OHgr;⋅cm.©1997 American Institute of Physics.
ISSN:0003-6951
DOI:10.1063/1.120450
出版商:AIP
年代:1997
数据来源: AIP
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53. |
Comment on “Including getter effect in a numerical contrast calculation for micrographs: A numerical contrast calculation for electron beam induced current at gettered dislocations” [Appl. Phys. Lett.69, 4090 (1996)] |
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Applied Physics Letters,
Volume 71,
Issue 15,
1997,
Page 2216-2216
C. Donolato,
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ISSN:0003-6951
DOI:10.1063/1.119385
出版商:AIP
年代:1997
数据来源: AIP
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