Spectroscopic And Electronic Investigation Of Some Complexes Deposited As Thin Films

Throughout this work, CuTCNQ thin films were prepared and investigated as an organometalic complex. CuTCNQ has special features that motivated the interest of researchers for years. It can be prepared at room temperature. It can be easily deposited in thiCuTCNQ was prepared in thin film form utilizing chemical reaction deposition. It has been found that the characteristics of the deposited film significantly depend upon the reaction time. Despite the deposited films have single chemical formula C12N4H4Cu,According to the spectroscopic investigation in the IR and UV ranges there was no significant difference between the two phases of the CuTCNQ. In addition, the main groups and bands of CuTCNQ have been assigned and detected for both phases. It is concludeRegarding the X-ray study, for the first time the diffraction pattern of both phases has been indexed. The indexing has also been performed for both phases at room temperature, at -100oC and at 90 oC. As a result of the X-ray analysis, the crystal structuFrom the electrical properties study of CuTCNQ thin film, it has been found that thermal activation energy is involved in the conduction. In other words the resistivity tends to decrease with increasing temperature as in semiconducting materials. The invoConsidering the AC conductivity of CuTCNQ thin films it has been found that both phases conduct a dispersive relationship with a frequency exponent factor s varies between 0.7 and 0.95. For both phases, it has been concluded that, regarding the frequency For the first time the dielectric properties of both phases of CuTCNQ were reported which might be important for the technological applications.Finally as an application of CuTCNQ, the characteristics of CuTCNQ as an electronic switch and as a memory device has been identified. From this study, the switching and memory parameters such as threshold voltage, switching time and delay time were estimFollowing are the general conclusions extracted from this study:1- CuTCNQ has two morphologies recognized as phase1 and phase2.2- Both phases have the same chemical formula but different in the physical properties.3- CuTCNQ is a charge transfer complex with a charge transfer of degree about 0.5.4- Phase 1 crystallizes in monoclinic structure while phase 2 has the triclinic structure.5- Structurally phase 2 can be transformed to phase 1 through heating up to 90 oC.6- CuTCNQ behaves as n-type semiconductor with density of charge carriers in order of 1025 cm-3 for phase 1.7- Energy of activation was evolved in order of 0.11 ev to 0.19 ev for phase 1.8- Phase 2 have two activation energies low activation energy resembles that of phase 1 in the high temperature region and high activation energy value of which is two times or more the value of low activation energy.9- CuTCNQ has a dispersive conductivity with frequency exponent factor consistent with the CBH model.10- From the value of hopping energy and activation energy value, the AC conduction is concluded to be due to single polaron hopping.11- The dielectric properties of both phases of CuTCNQ thin films were first reported and investigated against temperature, frequency and film thickness.12- Phase 2 of CuTCNQ has, to some extent, the ability to be technically used as an electric switch on form of Cu/TCNQ/Cu device since:a. It is easy to be prepared in any laboratory without any technical problems.b. It has a reasonable value of threshold voltage ~ 28 V.c. Its switching mechanism is reversible with certain controlled time.d. It is reliable and can be repeated as an electronic switch for many times.e. No moisture effect was detected.13- However more research is required to adjust and optimize the switching time with the film characteristics.