First-Principles Study Of The Electronic Transport Properties Of Ⅲ-Ⅴ And Ⅳ-Ⅵ Nanocluster Devices

Nanoelectronic devices are expected to be one of the most promising candidates inthe application of future electronic production due to their advantages of small size, lowcost, low energy consumption and so on. The size of molecular device is so small (aboutseveral nanometers) that it may break the Moore’s law limit. Many materials have beenreported can be used in molecular devices, such as C60, graphene and small organicmolecules which are mainly organic materials. However, we put our focus on inorganicmaterials in this report. We investigate the geometric structures and transport propertiesof (GaAs)_n,(InAs)_n,(PbS)_nand (PbSe)_n(n=2-4) cluster-based junctions using thefirst-principles calculation based on density functional theory (DFT) combined withnonequilibrium Green’s function (NEGF).We obtain some interesting properties in our calculation. All the twelve molecularjunctions show metallic behavior in low bias voltage regions and then the currents beginto decrease when the voltage increases to some high point (about2.0-2.6V) which giverise to the negative differential resistance (NDR) feature.In this report, we first briefly introduce nanoelectronics and nanoelectronic devicesand then we outline the theoretical fundamentals of first-principles theory, Green’sfunction as well as the calculating method and process for transport properties. In themajor part, we design some innovative molecular devices and study their transportproperties. For the same kind of clusters with different number of atoms, wecomparatively studied their transport properties. The mechanisms of the transportproperties of all the nanocluster-based devices are proposed to provide theoretical supportto the fabrication of practical functional molecular devices.The research in this program will open a door to the inorganic nanoelectronic devicesin the field of nanometer electronics. In addition, the investigation to these interestingjunctions will offer some theoretical support to the fabrication of practical moleculardevices in future.