Critical current of HTS 2G tape operating under high-frequency triangular wave current with DC bias

Author(s):  
Pawel Lasek ◽  
Jaroslaw Michalak ◽  
Mariusz Stepien
2013 ◽  
Vol 8 (2) ◽  
pp. 78-82
Author(s):  
B. Padmanabhan ◽  
D. Vasileska ◽  
S. M. Goodnick

Current collapse phenomenon that occurs in GaN HEMTs under a moderately large DC bias stress, poses serious problems for usage of GaN technology in high-power high-frequency applications from a reliability standpoint. Additional problem in these devices operated at high biases is the appearance of self-heating effects that degrade device characteristics and, as shown in this work further amplify the problem of current collapse by changing the device electrostatics.


1996 ◽  
Vol 10 (01n02) ◽  
pp. 51-60
Author(s):  
X.L. LEI ◽  
N.J.M. HORING ◽  
H.L. CUI ◽  
K.K. THORNBER

We examine the frequency-dependence of carrier drift-velocity in superlattice miniband conduction for a small signal ac electric field superposed on a dc bias E0. Our determination of the differential mobility is based on an accurate microscopic treatment of phonon and impurity scatterings. At finite E0, the differential mobility exhibits anomalous frequency-dependence: its real part exhibits a broad hump before finally approaching zero at high frequency, and its imaginary part has a marked dip to negative values before going through the conventional maximum. A simple dual-parameter empirical formula adapted from velocity overshoot studies provides excellent fits to this unusual behavior.


2015 ◽  
Vol 1805 ◽  
Author(s):  
Mark Stewart ◽  
Markys G Cain

ABSTRACTThe Laser Intensity Modulation Method, LIMM, has been used to investigate the poling state of ceramic piezoelectric thin films. The frequency of the system has been extended to 70MHz to enable films of thicknesses down to 100nm to be measured. A unique development has been to sweep the DC bias applied to the sample whilst performing the LIMM measurement, thus giving pseudo PE loops. These PE loops are unique in that they represent the polarization state within a distinct depth of the film, whereas normally PE loops are a result of the complete film. This allows us to investigate processes occurring within different regions of the film.


Author(s):  
Syed N. R. Kazmi ◽  
Amal Z. Hajjaj ◽  
Pedro M. F. J. Costa ◽  
Mohammad I. Younis

We report an analytical and experimental study on the tunability of in-plane doubly-clamped nanomechanical arches under varied DC bias conditions at room temperature. For this purpose, silicon based shallow arches are fabricated using standard e-beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a transduction gap of 1 μm between the beam and the driving/sensing electrodes. The high tunability of shallow arches paves the ways for highly tunable band pass filtering applications in high frequency range.


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