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Nanoelectronics: Basic Concepts, Approaches, and Applications
Published in Rakesh K. Sindhu, Mansi Chitkara, Inderjeet Singh Sandhu, Nanotechnology, 2021
Balwinder Kaur, Radhika Marwaha, Subhash Chand, Balraj Saini
Quantum tunneling refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount. Classical mechanics could not explain this phenomenon. The difference arises because classical mechanics treated matter as solely particles, whereas quantum mechanics emphasizes upon wave-like character of material particles, i.e., dual character of matter. Heisenberg’s uncertainty principle imposes a limit on the simultaneous measurement of position and momentum of particles accurately and forms the basis. It implies that there are no regions of zero probability; hence, the probability of the given particle to exist on the opposite side of the barrier is nonzero, which leads to its tunneling on another side of the barrier.
Characterization Techniques of Nanoparticles Applied in Drug Delivery Systems
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Vipin Kumar Sharma, Daphisha Marbaniang
This technique is based on the principle of quantum tunneling. When a conducting tip is brought very near to a metallic or semi-conducting surface, a bias between the two can allow electrons to tunnel through the vacuum between them. For low voltages, this tunneling current is a function of the local density of states at the Fermi level of the sample. Variations in current as the probe passes over the surface are translated into an image. In this technique, good resolution is considered to be 0.1 nm lateral resolution and 0.01 nm depth resolution. The images are normally generated by holding the current between the tip of the electrode and the specimen surface while the tip is piezoelectrically scanned in a raster pattern over the region of the specimen surface being imaged, by holding the force rather than the electric current between the tip and the specimen at a set-point value. When the height of the tip is plotted as a function of its lateral position over the specimen, an image results looking very much like the surface topography. This technique can be applied not only in an ultra-high vacuum (UHV) but also in air and various other liquid or gas states. However, extremely clean surfaces and sharp tips are required, which makes it challenging as a technique.
Introduction
Published in D I Arun, P Chakravarthy, R Arockiakumar, B Santhosh, Shape Memory Materials, 2018
D I Arun, P Chakravarthy, R Arockiakumar, B Santhosh
Another of the most advanced stimuli-responsive materials of interest is QTC. Quantum tunneling is a quantum mechanical process by which minute particles (quantum particles and electrons in a material) pass through a barrier that they generally would not be able to as per the classical theories of physics. This is significant because, if the potential energy barrier is higher than the energy of the particle, the barrier becomes impassible according to classical physics, whereas the theories according to quantum mechanics explain the possibility of the particle making it through. A polymer–metal composite material containing a nonconducting elastomeric binder can be used as a pressure sensor, and this is based on the principle of quantum tunneling. Similar to the piezoelectric mechanism, the application of pressure causes the reduction of resistance to the path of electrons and thus conducts electricity, which otherwise behaves as an insulator in absence of pressure.
Energy Analysis of Metal QCA Circuits Behavior Based on Particle-Wave Duality
Published in IETE Journal of Research, 2022
Masoumeh Shirichian, Reza Akbari-Hasanjani, Reza Sabbaghi-Nadooshan
When a quantum particle with energy E confronts a potential barrier of a finite height V0 where V0 > E, the particle can penetrate the barrier, a classically forbidden phenomenon, named quantum tunneling. The wave aspect of this phenomenon is depicted in Figure 4 where an incident wave (showing the probability distribution of a particle's position) approaches a potential barrier from the left and results in a reflected wave traveling to the left, and a transmitted one traveling to the right.