A transfer hamiltonian model for devices based on quantum dot arrays.

S Illera,A Cornet,J D Prades,A Cirera

doi:10.1155/2015/426541

Abstract

We present a model of electron transport through a random distribution of interacting quantum dots embedded in a dielectric matrix to simulate realistic devices. The method underlying the model depends only on fundamental parameters of the system and it is based on the Transfer Hamiltonian approach. A set of noncoherent rate equations can be written and the interaction between the quantum dots and between the quantum dots and the electrodes is introduced by transition rates and capacitive couplings. A realistic modelization of the capacitive couplings, the transmission coefficients, the electron/hole tunneling currents, and the density of states of each quantum dot have been taken into account. The effects of the local potential are computed within the self-consistent field regime. While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide.

Highlights

The demand for increasing the integrated density devices has led to the emergency of a whole generation devices based on confined structures
While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide
An intuitive theoretical framework suitable for this purpose is available in the noncoherent rate equations

Summary

Introduction

The demand for increasing the integrated density devices has led to the emergency of a whole generation devices based on confined structures. If first-principles calculations for single tunnel events were implemented, the huge effort required would make the simulation time increase in an unacceptable manner This impractical computational time forced us to write a compact model with some assumptions and relax the expectation of accuracy when treating with few-electron devices operating through quantum features. The hole transport was introduced obtaining new current terms and realistic expressions for the capacity in bipolar conduction All of these have been implemented in a computational code conforming a powerful transport simulation tool that allows reproducing, explaining, and predicting the behavior of multiple devices based on Qds. we present details about the computational implementation. In order to show the capabilities of the presented methodology, two examples of practical implementations of Qd-based devices were simulated: one single Qd and a multilayer structure that conform the basic building block of future devices based on Qds

The Model

Application and Discussion

Conclusions