We have developed analytical models for bias dependent contact resistance (RC) and output charact... more We have developed analytical models for bias dependent contact resistance (RC) and output characteristics of staggered organic field-effect transistors (OFETS) based on a bulk resistance-approximated and mobility-modified current-crowding method. Numerical evaluations of RC and its resistive components show that the bias dependency of the bulk resistance is negligible. Consequently, the properties of the active layer interfaces determine RC and its characteristics. Effective parameters include a normally constant charge injection barrier at the organic-metal interface (Eb) and a gate induced surface carrier-concentration (PS0) at the organic-insulator boundary. The energy barrier pertains to the fabrication process, and its related resistance (rc) can be determined as the fitting parameter of the theoretical model. However, PS0 is strongly gate bias dependent and the results of the numerical model indicate that the resulting component (rch) is dominant and has a considerable effect ...
In this paper we have investigated theoretically the effect of top gate voltage on the threshold ... more In this paper we have investigated theoretically the effect of top gate voltage on the threshold voltage of a double gate organic field effect transistor. We have solved the 1-D Poisson's equation in organic semiconductor active layer of this structure. Using the calculated local potential profile in the active layer, the total surface charge density was obtained. By considering the linear variation of this charge quantity with bottom gate voltage, the modulation of threshold voltage was studied as a function of different top gate voltages. It appears that the shielding effect of the top gate charges attenuates the effect of top gate voltage on the threshold voltage. In situations where shielding charges do not exist, the top gate voltage drastically affects the threshold voltage.
In this Letter, we have introduced a technique, new to our knowledge, to fabricate gratings on a ... more In this Letter, we have introduced a technique, new to our knowledge, to fabricate gratings on a waveguide of azo-functionalized polymeric films using a slit mask and a fast, direct-writing method. To prevent the destruction of the waveguide by the grating formation on the waveguide, we placed a slit mask on the waveguide. By properly adjusting the resonance, this grating can be used as an integrated wavelength filter. We have produced an attenuation of 13.4 dB at 1562 nm with a FWHM of 3.45 nm. The grating has been fabricated as narrow as the width of the waveguide to couple filtered light into the waveguide by using a slit mask. Any light shifted from the resonance will pass through the waveguide undisturbed.
We have developed analytical models for bias dependent contact resistance (RC) and output charact... more We have developed analytical models for bias dependent contact resistance (RC) and output characteristics of staggered organic field-effect transistors (OFETS) based on a bulk resistance-approximated and mobility-modified current-crowding method. Numerical evaluations of RC and its resistive components show that the bias dependency of the bulk resistance is negligible. Consequently, the properties of the active layer interfaces determine RC and its characteristics. Effective parameters include a normally constant charge injection barrier at the organic-metal interface (Eb) and a gate induced surface carrier-concentration (PS0) at the organic-insulator boundary. The energy barrier pertains to the fabrication process, and its related resistance (rc) can be determined as the fitting parameter of the theoretical model. However, PS0 is strongly gate bias dependent and the results of the numerical model indicate that the resulting component (rch) is dominant and has a considerable effect ...
In this paper we have investigated theoretically the effect of top gate voltage on the threshold ... more In this paper we have investigated theoretically the effect of top gate voltage on the threshold voltage of a double gate organic field effect transistor. We have solved the 1-D Poisson's equation in organic semiconductor active layer of this structure. Using the calculated local potential profile in the active layer, the total surface charge density was obtained. By considering the linear variation of this charge quantity with bottom gate voltage, the modulation of threshold voltage was studied as a function of different top gate voltages. It appears that the shielding effect of the top gate charges attenuates the effect of top gate voltage on the threshold voltage. In situations where shielding charges do not exist, the top gate voltage drastically affects the threshold voltage.
In this Letter, we have introduced a technique, new to our knowledge, to fabricate gratings on a ... more In this Letter, we have introduced a technique, new to our knowledge, to fabricate gratings on a waveguide of azo-functionalized polymeric films using a slit mask and a fast, direct-writing method. To prevent the destruction of the waveguide by the grating formation on the waveguide, we placed a slit mask on the waveguide. By properly adjusting the resonance, this grating can be used as an integrated wavelength filter. We have produced an attenuation of 13.4 dB at 1562 nm with a FWHM of 3.45 nm. The grating has been fabricated as narrow as the width of the waveguide to couple filtered light into the waveguide by using a slit mask. Any light shifted from the resonance will pass through the waveguide undisturbed.
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