Generation and recombination in two-dimensional bipolar transistors

, Article Applied Physics A: Materials Science and Processing ; Vol. 115, issue. 3 , 2014 , pp. 737-740 ; ISSN: 00304018 Gharekhanlou, B ; Khorasani, S ; Sharif University of Technology

2014

Abstract

We study the effects of recombination and generation process on the operation of bipolar junction transistor based on two-dimensional materials, and in particular, graphone. Here, we use Shockley-Read-Hall model to study these process. First, we investigate the current-voltage characteristics of a graphone p-n junction considering generation and recombination process. Then, we calculate the estimated changes in current gain, cutoff frequency, and output characteristics of a graphone bipolar junction transistor designed in a recent study

An overview of tight-binding method for two-dimensional carbon structures

, Article Graphene: Properties, Synthesis and Applications ; 2012 , Pages 1-36 ; 9781614709497 (ISBN) Gharekhanlou, B ; Khorasani, S ; Sharif University of Technology

2012

Abstract

Since the advent of graphene, the two-dimension allotrope of carbon, there has been a growing interest in calculation of quantum mechanical properties of this crystal and its derivatives. To this end, the tight-binding model has been in frequent use for a relatively long period of time. This review, presents an in-depth survey on this method as possible to graphene and two of the most important related structures, graphene anti-dot lattice, and graphane. The two latter derivatives of graphene are semiconducting, while graphane is semimetallic. We present band structure and quantum mechanical orbital calculations and justify the results with the density function theory

Current-voltage characteristics of graphane p-n junctions

, Article IEEE Transactions on Electron Devices ; Volume 57, Issue 1 , 2010 , Pages 209-214 ; 00189383 (ISSN) Gharekhanlou, B ; Khorasani, S ; Sharif University of Technology

2010

Abstract

In contrast to graphene, which is a gapless semiconductor, graphane, the hydrogenated graphene, is a semiconductor with an energy gap. Together with the 2-D geometry, unique transport features of graphene, and the possibility of doping graphane, p and n regions can be defined so that 2-D p-n junctions become feasible with small reverse currents. This paper introduces a basic analysis to obtain the current-voltage characteristics of such a 2-D p-n junction based on graphane. As we show, within the approximation of Shockley's law of junctions, an ideal I-V characteristic for this p-n junction is to be expected

Lattice heat capacity of mesoscopic nanostructures

, Article Journal of Physics: Conference Series, 5 July 2010 through 10 July 2010, Dubna ; Volume 248 , 2010 ; 17426588 (ISSN) Gharekhanlou, B ; Khorasani, S ; Vafai, A ; Sharif University of Technology

2010

Abstract

We present a rigorous full quantum mechanical model for the lattice heat capacity of mesoscopic nanostructures in various dimensions. Model can be applied to arbitrary nanostructures with known vibrational spectrum in zero, one, two, or three dimensions. The limiting case of infinitely sized multi-dimensional materials are also found, which are in agreement with well-known results. As examples, we obtain the heat capacity of fullerenes

Tight-binding description of patterned graphene

, Article Semiconductor Science and Technology ; Volume 23, Issue 7 , 2008 ; 02681242 (ISSN) Gharekhanlou, B ; Alavi, M ; Khorasani, S ; Sharif University of Technology

2008

Abstract

The existence of an energy gap of graphene is vital as far as nano-electronic applications such as nano-transistors are concerned. In this paper, we present a method for introducing arbitrary energy gaps through breaking the symmetry point group of graphene. We investigate the tight-binding approximation for the dispersion of π and π* electronic bands in patterned graphene including up to five nearest neighbors. As we show by applying special defects in graphene structure, an energy gap appears at Dirac points and the effective mass of fermions also becomes a function of the number of defects per unit cell. © 2008 IOP Publishing Ltd

Bipolar transistor based on graphane

, Article Journal of Physics: Conference Series, 5 July 2010 through 10 July 2010 ; Volume 248 , 2010 ; 17426588 (ISSN) Gharekhanlou, B ; Tousaki, S. B ; Khorasani, S ; Sharif University of Technology

2010

Abstract

Graphane is a semiconductor with an energy gap, obtained from hydrogenation of the two-dimensional grapheme sheet. Together with the two-dimensional geometry, unique transport features of graphene, and possibility of doping graphane, p and n regions can be defined so that p-n junctions become feasible with small reverse currents. Our recent analysis has shown that an ideal I-V characteristic for this type of junctions may be expected. Here, we predict the behavior of bipolar juncrion transistors based on graphane. Profiles of carriers and intrinsic parameters of the graphane transistor are calculated and discussed

Two-dimesional Bipolar Junction Transistors

, Ph.D. Dissertation Sharif University of Technology Gharekhanlou, Behnaz (Author) ; Khorasani, Sina (Supervisor) ; Sarvari, Reza (Supervisor)

Abstract

In this thesis, we present for the first time a unified and extensive theory of two-dimensional bipolar junction transistors fabricated on mono-layer materials. Unlike their bulk counterparts which are described by the conventional theory of bulk junctions, the proposed class of structures behaves here significantly different and needs an entirely different theory. This has been based on the theory of planar p-n rectifying junction diodes developed in an earlier study of ours, where we had investigated a basic p-n junction model with abrupt doping profile. The accuracy of theory is limited to the applicability of drift-diffusion model with depletion-layer approximation, while disregarding...

Investigation of the Synergism Between Engineered Stem Cells with Vtk Containing Construct and Electrical Stimulation in Osteogenic Differentiation

, M.Sc. Thesis Sharif University of Technology Gharaei, Mohammad Saleh (Author) ; Alemzadeh, Iran (Supervisor) ; Bakhshandeh, Behnaz (Supervisor) ; Saadatmand, Maryam (Co-Supervisor)

Abstract

In recent years, advances in medical science and increasing the level of healthcare have increased the life expectancy index; But in the meantime, a phenomenon called “diseases related to life expectancy” has appeared. Bone and skeletal diseases have a significant share in this category because the passage of time reduces bone mineral density and this is the source of many diseases, including osteoporosis. Current bone therapies, which include autologous and allogeneic bone grafts, will not meet this high need. Bone tissue engineering has been proposed as a potential alternative to solve this challenge. In bone tissue engineering, the essential components required for bone formation and...