Resonant tunneling devices

The proposed technique seems to be rather promising for the formation of electronic devices of extremely small sizes. In fact, its resolution is about 0.5-0.8 nm, which is comparable to that of molecular beam epitaxy. However, molecular beam epitaxy is a complicated and expensive technique. All the processes are carried out at 10 vacuum and repair extrapure materials. In the proposed technique, the layers are synthesized at normal conditions and, therefore, it is much less expansive. The presented results had demonstrated the possibility of the formation of superlattices with this technique. The next step will be the fabrication of devices based on these superlattices. To begin with, two types of devices wiU be focused on. The first will be a resonant tunneling diode. In this case the quantum weU will be surrounded by two quantum barriers. In the case of symmetrical structure, the resonant... 

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... 

We have demonstrated electrografting of a short alkyl-chain i.e. octyltrichlorosilane (OTS) and a new o-jt molecular rectifier i.e. 5-(4-undecenyloxyphenyl)-10,15,20-triphenylporphyrin(2) (TPP-C11) monolayers on hydrated Si (111) surfaces at room temperature. These results demonstrate that electrografting can be utilized for the development of other molecular devices, such as rectifiers, resonant tunnel diodes, transistors etc. 

Quantum effects, such as resonant tunneling, enhanced carrier mobility (two-dimensional electron gas), bound states in the optical absorption spectrum, and nonlinear optical effects (e.g., intensity-dependent refractive indices) have been observed in semiconductor multiple quantum wells (2-4), Examples of devices based on these structures include tunnel diodes, fast optical and optoelectronic switches, high electron mobility transistors, and quantum well lasers. 

A number of methods are available for the characterization and examination of SAMs as well as for the observation of the reactions with the immobilized biomolecules. Only some of these methods are mentioned briefly here. These include surface plasmon resonance (SPR) [46], quartz crystal microbalance (QCM) [47,48], ellipsometry [12,49], contact angle measurement [50], infrared spectroscopy (FT-IR) [51,52], Raman spectroscopy [53], scanning tunneling microscopy (STM) [54], atomic force microscopy (AFM) [55,56], sum frequency spectroscopy. X-ray photoelectron spectroscopy (XPS) [57, 58], surface acoustic wave and acoustic plate mode devices, confocal imaging and optical microscopy, low-angle X-ray reflectometry, electrochemical methods [59] and Raster electron microscopy [60]. 

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