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Full-Text Articles in Engineering
Investigation Of Nanoporous Thin-Film Alumina Templates, Biswajit Das
Investigation Of Nanoporous Thin-Film Alumina Templates, Biswajit Das
Electrical & Computer Engineering Faculty Research
This paper presents the results of a systematic study of the fabrication of thin-film alumina templates on silicon and other substrates. Such templates are of significant interest for the low-cost implementation of semiconductor and metal nanostructure arrays. In addition, thin-film alumina templates on silicon have the potential for nanostructure integration with silicon electronics. Formation of thin-film alumina templates on silicon substrates was investigated under different fabrication conditions, and the dependence of pore morphology and pore formation rate on process parameters was evaluated. In addition, process conditions for improved pore size distribution and periodicity were determined. The template/silicon interface, important for …
Low Frequency Noise In Gan Metal Semiconductor And Metal Oxide Semiconductor Field Effect Transistors, S. L. Rumyantsev, N. Pala, M. S. Shur, R. Gaska, M. E. Levinshtein, M. Asif Khan, Grigory Simin, X. Hu, J. Yang
Low Frequency Noise In Gan Metal Semiconductor And Metal Oxide Semiconductor Field Effect Transistors, S. L. Rumyantsev, N. Pala, M. S. Shur, R. Gaska, M. E. Levinshtein, M. Asif Khan, Grigory Simin, X. Hu, J. Yang
Faculty Publications
The low frequency noise in GaNfield effect transistors has been studied as function of drain and gate biases. The noise dependence on the gate bias points out to the bulk origin of the low frequency noise. The Hooge parameter is found to be around 2×10−3 to 3×10−3.Temperature dependence of the noise reveals a weak contribution of generation–recombination noise at elevated temperatures.
Electric Field Mapping System With Nanosecond Temporal Rosolution, F. E. Peterkin, R. Block, K. H. Schoenbach
Electric Field Mapping System With Nanosecond Temporal Rosolution, F. E. Peterkin, R. Block, K. H. Schoenbach
Bioelectrics Publications
The electric field dependence of the absorption coefficient in semi‐insulating GaAs at the absorption edge was measured in a high‐voltage pulsed experiment. Pulse duration was kept below 50 ns in order to avoid thermal effects. A GaAs laser diode was used as a probe light source with wavelength varied from 902 to 911 nm. For fields up to 40 kV/cm the absorption coefficient increased from 3 to 17 cm−1 at 902 nm, with smaller absolute increases evident at the longer wavelengths. Calculation from theory was consistent with this behavior. The spatial variation of the electric field was also recorded …
Supralinear Photoconductivity Of Copper Doped Semi-Insulating Gallium Arsenide, K. H. Schoenbach, R. P. Joshi, F. Peterkin, R. L. Druce
Supralinear Photoconductivity Of Copper Doped Semi-Insulating Gallium Arsenide, K. H. Schoenbach, R. P. Joshi, F. Peterkin, R. L. Druce
Bioelectrics Publications
We report on the intensity dependent supralinear photoconductivity in GaAs:Si:Cu material. The results of our measurements show that the effective carrier lifetime can change over two orders of magnitude with variations in the intensity of the optical excitation. A threshold intensity level has been observed and can be related to the occupancy of the deep copper level. Numerical simulations have also been carried out to analyze the trapping dynamics. The intensity dependent lifetimes obtained from the simulations match the experimental data very well. Finally, based on the nonlinear intensity dependence of the effective lifetimes, a possible low‐energy phototransistor application for …
Impact Of Field-Dependent Electronic Trapping Across Coulomb Repulsive Potentials On Low Frequency Charge Oscillations, R. P. Joshi, K. H. Schoenbach, P. K. Raha
Impact Of Field-Dependent Electronic Trapping Across Coulomb Repulsive Potentials On Low Frequency Charge Oscillations, R. P. Joshi, K. H. Schoenbach, P. K. Raha
Bioelectrics Publications
We have performed Monte Carlo simulations to obtain the field dependence of electronic trapping across repulsive potentials in GaAs. Such repulsive centers are associated with deep level impurities having multiply charged states. Our results reveal a field‐dependent maxima in the electronic capture coefficient, and the overall shape is seen to depend on the background electron density due to the effects of screening. Based on the Monte Carlo calculations, we have examined the stability of compensated semiconductors containing such repulsive centers. Our analysis indicates a potential for low frequency charge oscillations which is in keeping with available experimental data.
Temporal Development Of Electric Field Structures In Photoconductive Gaas Switches, K. H. Schoenbach, J. S. Kenney, F.E. Peterkin, R. J. Allen
Temporal Development Of Electric Field Structures In Photoconductive Gaas Switches, K. H. Schoenbach, J. S. Kenney, F.E. Peterkin, R. J. Allen
Bioelectrics Publications
The temporal development of the electric field distribution in semi‐insulating GaAs photoconductive switches operated in the linear and lock‐on mode has been studied. The field structure was obtained by recording a change in the absorption pattern of the switch due to the Franz–Keldysh effect at a wavelength near the band edge of GaAs. In the linear mode, a high field layer develops at the cathode contact after laser activation. With increasing applied voltage, domainlike structures become visible in the anode region and the switch transits into the lock‐on state, a permanent filamentary electrical discharge. Calibration measurements show the field intensity …
Bistable Behavior Of The Dark Current In Copper-Doped Semi-Insulating Gallium Arsenide, R. A. Roush, K. H. Schoenbach, R. P. Brinkmann
Bistable Behavior Of The Dark Current In Copper-Doped Semi-Insulating Gallium Arsenide, R. A. Roush, K. H. Schoenbach, R. P. Brinkmann
Bioelectrics Publications
The dark current characteristics of gallium arsenide doped with silicon and compensated with diffused copper were found to have a pronounced region of current controlled negative differential conductivity (ndc) similar to the characteristics of a thyristor. The resistivity of the semi‐insulating semiconductor was measured to be 105 Ω cm for applied voltages up to 2.2 kV, which corresponds to an average electric field of 38 kV/cm. At higher voltages, a transition to a stable high current state was observed with a current rate of rise exceeding 1011 A/s. There is evidence of the formation of at least one …