Circuit Model of Different Quantum Dot Based Field Effect Transistors

Abstract

A quantum dot is a semiconductor nanostructure that confines the motion of conduction band electrons, valence band holes, or excitons (bound pairs of conduction band electrons and valence band holes) in all three spatial directions. The confinement can be due to electrostatic potentials (generated by external electrodes, doping, strain, impurities), the presence of an interface between different semiconductor materials (e.g. in core-shell nanocrystal systems), the presence of the semiconductor surface (e.g. semiconductor nanocrystal), or a combination of these. The presence of quantum dots in the metal-oxide-semiconductor field effect transistor (FET) structure produces different characteristics of the FET. Based on different characteristics of the FET, different multi-valued logic can be implemented using QD based FETs. The presence of quantum dots in the gate region of a FET can generate three states (QDGFET) or make the FET act like a nonvolatile memory (QDNVM), whereas a quantum dot in the channel of the FET (QDCFET) produces four states in the transfer characteristics. This paper presents the development of circuit models for different types of FET having QDs in their different regions such as in the gate region (QDGFET/QDNVM) or in the gate region as well as in the channel region (QDG-QDCFET).