Quantum state depression in quantum well devices

Tavkhelidze, A. and Svanidze, V. (2008) Quantum state depression in quantum well devices. In: The 21 International Vacuum Nanoelectronics Conference IVNC2008, Wroclaw, 13-17 July, Poland.

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Abstract

Development of semiconductor heterostructures enables quantum well (QW) devices. QW MOSFET transistors, lasers, and solar cells, are fabricated. Recently, new quantum size effect, quantum state depression (QSD) was investigated both theoretically [1] and experimentally [2] in metal QW. QSD is based on the ridged geometry of QW boundary. The ridges impose additional boundary conditions on electron wave function and some quantum states become quantum-mechanically forbidden. Quantum state density Ns is reduced. Electrons from forbidden energy levels have to occupy higher energy levels and Fermi energy EF increase. In semiconductor, QSD reduce nS within of all energy bands and rejected electrons occupy empty levels in empty bands). QSD has the same effect as conventional donor doping. It depends on electron confinement and therefore, is most pronounced in QW structures. For instance, nS is dramatically reduced in ridged quantum well (RQW) with respect to conventional QW of the same width. This allows fabrication of a wide RQW with quantum properties. As RQW is wider, it becomes possible to adjust it’s width, using the charge depletion like in a MOSFET transistor channel. It follows that fabricating of a RQW with tunable energy levels and tunable EF becomes technologically feasible. Such QRW can be used in the channel of ballistic MOSFET transistor and other QW based devices.

Item Type: Conference or Workshop Item (Paper)
Subjects: T Technology > T Technology (General)
Divisions: Faculties/Schools > School of Natural Sciences and Engineering
Depositing User: Professor Avtandil Tavkhelidze
Date Deposited: 05 May 2014 12:52
Last Modified: 02 Apr 2015 08:12
URI: http://eprints.iliauni.edu.ge/id/eprint/1420

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