Tunneling devices

The aim of this chapter is to acquaint the reader the physical principles of SE tunneling devices to be used in nanoelectronics. Based on this the charge transport properties of nanocluster assemblies in one, two and three dimensions will be discussed. By means of selected examples it will be demonstrated that ligand-stabilized nanoclusters of noble metals may be suitable building blocks for nanoelectronic devices. 

R. Kiehl, Complementary Heterostructure FET Integrated Circuits T. Ishibashi, GaAs-Based and InP-Based Heterostnicture Bipolar Transistors H. C. Liu and T. C. L. G. Sollner, High-Frequency-Tunneling Devices H. Ohnishi, T. More, M. Takatsu, K. Imamura, and N. Yokoyama, Resonant-Tunneling Hot-Electron Transistors and Circuits... 

A schematic view of the nanomechanical GMR device to be considered is presented in Fig. 1. Two fully spin-polarized magnets with fully spin-polarized electrons serve as source and drain electrodes in a tunneling device. In this paper we will consider the situation when the electrodes have exactly opposite polarization. A mechanically movable quantum dot (described by a time-dependent displacement x(t)), where a single energy level is available for electrons, performs forced harmonic oscillations with period T = 2-k/uj between the leads. The external magnetic field is perpendicular to the orientation of the magnetization in both leads. 

In this work, we present a brief introduction to the nonequilibrium Green s function method and discuss two important examples in which nonequli-brium Green s functions can be employed (1) electric current calculations in molecular tunneling devices and (2) in quantum dot-sensitized solar cells. 

An RF-only hexapole is used in systems from Waters (Figure 5.7). In more recent Waters systems, it is replaced by an ion-tunnel device (see below). 

To better see the importance of the effect of the reduction of the critical thickness in stacked layers in future QD-based tunneling devices, we have realized a 10-bilayer stracture, in which the Ge deposited amount was kept constant in all layers. The Si spacer thickness between adjacent islands was chosen to be 2.5 nm, a value typically used in tuimeling devices. It is worth noting that as the height of capped islands in the first layer is about 7 run, the total thickness of the spacer layer is 9.5 nm. This amount was then kept constant in all layers. Fig. 3(b) shows a typical TEM of such a structure. In contrast to the image of Fig. 3(a), the present image clearly shows that the Si spacer layer is not thick enough to completely cover... 

Finally, metal nanopartides are under investigation as elements in future electronic nanodevices they can be used as nanowires, nanoislands and as electron confinements in single electron tunneling devices [33-35]. Therefore, the fabrication of nanopartides with very well-defined sizes and surface properties is particularly important. Molecular films at particle surfaces are essential for specific interactions between nanopartides and macromolecules, between nanopartides and substrates and for the positioning of nanopartides inside nanodectrode arrangements. Nanopartides are also of interest for nano-optoelectronic appUcations due to their spedfic optical properties. For this purpose, the synthesis of nanopartides with very small distributions in chemical composition, size and shape in microreactors is under investigation. 

Jansen R, Dash SP, Sharma S, Bin BC (2012) Silicon spintronics with ferromagnetic tunnel devices. Semicond Sci Technol 27 83001... 

Marpe M, Heuser C, Diesing D, Wucher A (2011) Internal electron emission in metal-insulator-meted thin film tunnel devices bombarded with keV aigon tmd gold-cluster projectiles. Nucl Instrum Methods Phys Res, Sect B 269 972-976... 

Typical nanopore devices require only two electrodes, one on either side of the nanopore. On the other hand, integration of one or more electrodes into a nanopore offers interesting prospects towards smart nanopore devices, e.g. enhanced capabilities for surface functionalisation improved control of pore transport (gating) fabrication of metallic nanopores via local electrodeposition or sensing (FET or tunnelling devices). Fig. 16 illustrates a few designs that we will return to in the text. 

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