Regiane Ragi

University of São Paulo | USP · Departamento de Engenharia Elétrica e de Computação (SEL) (São Carlos)

This paper presents a fully analytical model for the current-voltage (I–V) characteristics of Resonant Tunneling Diodes. Based on Tsu-Esaki formalism, we consider the full electrical potential distribution in the structure, including the space charge regions at the emitter and collector layers. In addition, we account for the scattering suffered by...

In this paper, we develop an analytical model for the resonant current-voltage ( I–V) characteristics of 2D-2D Resonant Tunneling Diodes. Starting from the Tsu-Esaki formalism, we consider the overall electrical potential distribution in the device layer structure, including the quantized space charge region in the emitter layer. Additionally, to...

In this paper, we present fully analytical closed-form expressions to provide the energy levels of finite quantum wells. The model accounts for unequal electronic effective masses in the well and barrier regions. The analytical expressions were validated by comparing the results provided by our model with those arising from the numerical solution o...

This paper develops a new compact model for the Q–V and C–V characteristics of cylindrical junctionless nanowire FETs in which the nanowire radius is large enough, in such a way that quantum confinement effects can be neglected. Our model is fully analytical and valid for all bias regimes, i.e., subthreshold, partial depletion, and accumulation. Th...

In this paper, we developed an analytical model for the $I{-}V$ characteristics of junctionless nanowire FETs (JLNWFETs) in which the radius of the nanowire is large enough to allow quantum confinement effects to be neglected. The model is valid for all bias regimes, subthreshold, depletion and accumulation, and it is fully analytical, do not req...

In this paper, we developed an analytical quantum-mechanical model for the $I-V$ characteristics of cylindrical nanowire junctionless MOSFETs. Our compact model is based on the Landauer formalism to describe the ballistic current transport, as well as in a novel approach to solve the coupled Schrödinger and Poisson equations, in which the radial po...

O ensino de física dos dispositivos semicondutores é absolutamente fundamental para o desenvolvimento da microeletrônica. Contudo, cursos introdutórios nesta área muitas vezes se limitam a apresentar modelos analíticos excessivamente simplificados, que possibilitam uma compreensão intuitiva, mas incapazes de captar toda a complexidade dos dispositi...

In this paper, we develop an analytical model for the prediction of the peak voltage and the current in the current–voltage characteristics of nanowire resonant tunneling heterostructures. The model is applied in the case study of double‐barrier InAs/InP devices, and the results are obtained from numerical carrier transport calculations, in terms o...

Purpose The purpose of this paper is to develop an efficient numerical algorithm for the self‐consistent solution of Schrodinger and Poisson equations in one‐dimensional systems. The goal is to compute the charge‐control and capacitance‐voltage characteristics of quantum wire transistors. Design/methodology/approach The paper presents a numerical...

In this paper a novel approach to the two dimensional self-consistent solution of Schrödinger and Poisson equations is implemented to calculate the free electron concentration and capacitance-voltage characteristics in semiconductor quantum wire transistors. The Schrödinger equation is solved by the split operator method while a relaxation method w...

This paper discusses the modeling and experimental results for a new family of electronic devices in which a Schottky metal is placed in direct contact to a low dimensionality structure such as a quantum-well or a quantum wire. Based on those principles, we experimentally demonstrate the improved performance of both a microwave varactor and a MSM p...

In this paper we derive the I-V characteristics of Schottky contacts based on bulk metal to semiconductor quantum wires interfaces. The obtained results show that quantum confinement is a strong reduction of the reverse saturation current when compared to conventional Schottky contacts. Numerical simulations are carried out to highlight the advanta...

This paper deals with the modeling of the electronic characteristics of semiconductor devices based on Schottky contacts in low-dimensional systems. For the capacitance-voltage characteristics, a quasi-two-dimensional quantum mechanical model is developed and validated. For the current-voltage characteristics, a unified model is presented, consider...

This paper addresses the capacitance-voltage (C-V) characteristics of heterodimensional Schottky diodes, in which the Schottky metal is placed in direct contact to a two-dimensional electron gas and the confined electron behavior directly dictates the device performance. We develop a novel quasi-2D model for the C-V characteristics of the device, b...

A novel gate controlled Schottky diode varactor is introduced. The three-terminal varactor is a modulation-doped heterostructure of AlGaAs/GaAs with two Schottky contacts, similar to a metal–semiconductor–metal (MSM) diode. Schottky metal contacts are made to a two-dimensional electron gas (2-DEG). The third contact, the gate contact is formed from...

Here we investigate some general properties of the so-called even circular state (ECS) produced in a cavity, consisting of a superposition of N coherent states |?k(k = 1,2,...,N) with the same |?k|. Several special states may emerge from this kind of superposition: in particular, when 1<<(e|?k|2/N)N<<4N a Fock state with N quanta is produced, where...

Using the well known Hartree-Fock Method we have considered two examples with possible analitical solution. In a �first example we considered two particle of half integer spin interacting by means of a force with harmonic dependence and in the second we approached the gas of free electron with a positive charge background. Those two examples were c...

In this comment we present an improvement of our recent proposal [Int. J. Mod. Phys. B12, 1495 (1998)] to generate a generalized superposition of two coherent states. The basic idea here is to use a dispersive atom-field interaction together with a single atom quantum state engineering.

We introduce a generalized superposition of two coherent states to investigate interference effects between them and their influences upon nonclassical effects. The role played by the involved parameters on each nonclassical effect is shown, including a proposal for generating this state and its application. The present scheme constitutes an unifie...