The Influence Of The Coulomb Blockage Effect On The Electron Transport Properties Of Quantum Devices

The theory of molecular electronics become more and more complete, and the science and technology of microelectronics are developing rapidly. The creation and preparation of miniaturization of electronic devices has become a hot research topic in the modern era of science and technology. More common and basic single molecular devices have a single electron transistors, molecular switch and molecular rectifier, and so on. However, the role of the coulomb blockade effect is particularly important in molecular devices researches; there is a certain auxiliary study of the coulomb blockage effect on the transport properties of molecular devices in this paper. The full text is divided into five chapters, respectively as follows,The first chapter, simply introduces the research background of molecular devices and coulomb blockade effect, and some of the related domestic and overseas research progress.The second chapter, systematically describes the basic knowledge and theories used in this article, such as the principle and structure of single molecular devices, coulomb blockade effect, the principle of single electron tunneling and the Kondo effect and the related content;The third chapter, introduce several methods which often used in the electron transport properties researches, mainly include the self-consistent field method, the master equation method and the non-equilibrium green function method based on the density functional theory. However, the self-consistent field method cannot deal with coulomb blockade effect, the master equation method can deal with coulomb blockade but limited under the condition of weak coupling. And the calculation result based on the non-equilibrium green’s function method with density functional theory is still controversial. This chapter also introduces the model and the non-equilibrium green’s function method based on the equation of motion in detail.The fourth chapter, under the condition of a given system model parameters, study the effect of Coulomb potential, temperature and coupling strength on the coulomb blockade, we found that when the quantum system is in the weak coupling region, the coulomb blockade effect will be weakened gradually along with the rise of temperature until it disappeared. When the system in low temperature condition, with the increase of coupling strength and the coulomb blockage effect also subsequently and weaker until it disappeared, this is consistent with the researchers’ conclusion before performance.The fifth chapter, research the coulomb blockade effect just disappear on the basis of the fourth chapter, and completed the research of the transition from coulomb blockade area to the non-coulomb blockade area, also compares the calculated current features employing the self-consistent field method and the non-equilibrium green’s function method based on the equation of motion adopted in this paper respectively. We found that when the parameters in the non-coulomb blockade area, coulomb blockade effect does not exist, based on the motion equation of non-equilibrium green’s function method and self-consistent field method are available, and when the parameters in the coulomb blockade area, only the function of green function method based on the equation of motion could be used to deal with the coulomb blockade problem better.Finally, the work of this paper is summarized, and puts forward some prospects for future work.