| For increasing the understanding of the organic semiconductor material, a brief introduction of the organic semiconductor material was given in this thesis first. It included the development history of the organic semiconductor material, the advantages and the applied foreground of such material, and the normal organic semi-conductor material, we also gave a brief for the electric theory of it.Compared with the inorganic semiconductor material, It has a large difference between the organic semiconductor material and it in either the electric quantity or the physical quantity, because of the special structure of the organic semiconductor material. So, we must design a reasonable measure plan for these different characters before we measure the electric property of the organic semiconductor material. In this thesis we analysis the character of the structure and the physics of the pentacene single crystal that we want to measure. In the experiment the enough stable constant current source and the voltage measure equipment with enough high input resistance are necessary in measuring because the resistance of pentacene is very high. In the measuring experiment. we should exclude the influence of the contact resistance because it is so large between the organic semi-conductor material and the metal electrode. The pentacene single crystal belongs to triclinic system, the resistance isn't same in the different direction, so we should exclude the error because of the anisotropism when we design the plan of measuring. And we also exclude the contact between the metal electrode and the material because the mechanical robustness. Considered the upper reason, we concern the measuring plan by the basic of the transmission line model (TLM) method after we study the measuring method of the semiconductor resistance and the contact resistance, TLM is usually used to measure the contact resistance of the film material. We can divide the term of the material resistance and the contact resistance directly by managing the data. The sample was processed to rectangle, the electrodes was extended to the underlay of the material and evaporated two parallel electrode for making the current between two electrodes symmetrical. The 236 source-measure unit of KEITHLEY company was used which can supply the constant current and the high input resistance. We measured the resistance and the contact resistance of the pentacene by using such method. In the last, we set up the modulation circuit of electro-optical modulator using an OFET, whose active material is CuPc supplied by the Institute of Applied Chemistry. Electro-optical modulator using crystal is normal method of optical signal modulation, the optic-electric effect of LiNdO3 crystal etc is used to modulate the optical signal. We used a voltage driving circuit to put the voltage to the optic-electrical crystal, the refractive index will change with the changing of the voltage between the two end of the crystal, and we realized the loading of the optical signal by changing the optical intensity transmitted the crystal. Now, the circuit which supplied the driving voltage for the crystal in the optic-electric modulation system is consist by the expensive high voltage operational amplifier or the complementary circuit with more complex structure. In this thesis, we fabricate a reverse amplification circuit as the modulation circuit of electro-optical modulator using an OFET and measure the modulation results of the light signal. In the process of the measuring, the Tektronix AFG310 random waveform generator supplied the sine signal and the square wave signal, the output voltage of the modulation circuit load to the end of the optic-electric crystal, the output light signal was accepted by the diode, and the diode was connected with the oscilloscope to show the output light intensity, a t the same time we used the oscilloscope to watch the input modulation signal. The tested results show: the plus and minus half cycle of the output waveform was anisomerous, the quie...
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