Molecular electronic devices

Introduction of molecular electronic devices, definition, simple molecular device,basic molecular devices,advantages,applications

1. MOLECULAR ELECTRONic DEVICES By Mrs.R.Chitra, Assistant Professor(SS), Department of ECE, School of Engineering, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore.

2. Introduction Molecular electronics is electronics made out of molecule or groups of molecules to perform the task identical to semiconductor transistors, diodes, memory and conductors. Molecular electronics is the study and application of molecular building blocks for the fabrication of electronic components. It is an interdisciplinary area that spans physics, chemistry, and materials science. The unifying feature is use of molecular building blocks to fabricate electronic components.

3. Molecular Electronics is a branch of nanotechnology that uses single molecules, or nano scale collections of single molecules, as electronic components. Because single molecules constitute the smallest stable structures possible, this miniaturization is the ultimate goal for shrinking electrical circuits. In single molecule electronics, the bulk material is replaced by single molecules The molecules used have properties that resemble traditional electronic components such as a wire, transistor, or rectifier. This concept of using a molecule as a traditional electronic component was first presented by Aviram and Ratner in 1974, when they proposed a theoretical molecular rectifier composed of donor and acceptor sites which are insulated from one another

4. Molecular electronics is conceptually different from conventional solid state electronics due to their physical and electronic properties tailored by synthesis methods, bringing a new dimension in design flexibility. Molecules are are small, identical. They have discrete energy levels called LUMO (Lowest Unoccupied Molecular Orbital) equivalent to the conduction band and HOMO (Highest Occupied Molecular Orbital) like the valence band separated by an energy gap. The molecules posses a special property called self assembly. Self assembly is a phenomenon in which atoms, molecules, or groups of molecules arrange themselves spontaneously into regular patterns and complex systems without outside interventions.

5. There are several reasons for molecules to be preferred: Molecules are small & Identical Assembly and recognition Dynamic stereochemistry Synthetic tailorability

6. A Simple Molecular device

7. Basic Molecular devices

8. Molecular Electronic Devices Monomolecular film devices(diodes, switches, memory). Single molecule FET Organic light emitting diode(OLED).

9. MOLECULAR DIODES Diodes are components that conduct current only in one direction, when they are forward biased. They are composed of semiconductor materials, and have a p-n junction and two terminals for the connections . There are two fundamental types of molecular diode .

10. MOLECULAR SWITCHES Semiconductor switches can be made on a very small scale Perform computational function when placed in right corner Molecular switches is orders of magnitude smaller

11. TYPES OF MOLECULAR SWITCHS Acidochromic molecular switches Photochromic molecular switches Host–guest molecular switches Mechanically-interlocked molecular switches .

12. MOLECULAR TRANSISTOR The term molecular transistors refers to switching circuits constructed from an individual molecule. The transistor in which individual molecules are utilized as the active electronic component is a longstanding challenge from both a fundamental and technological standpoint

13. MOLECULAR MEMORY Molecular memory is a term for data storage technologies that use molecular species as the data storage element, rather than e.g. circuits, magnetics, inorganic materials or physical shapes.

14. MOLECULAR FET An insulator separates the gate from the molecule . The gate is not designed to inject charge. Rather it influences the molecule’s potential.

15. MOLECULAR OLED A typical OLED is composed of a layer of organic materials situated between two electrodes, the anode and cathode, all deposited on a substrate. The organic molecules are electrically conductive as a result of delocalization of pi electrons caused by conjugation over part or all of the molecule.

16. Advantages of Of MOLECULAR ELECTRONICS Small Size High Speed Less Power Low manufacturing cost

17. APPLICATIONS OF MOLECULAR ELECTRONICS Molecular electronics has wide range of applications in the work areas of chemistry, physics, electronics and nano electronics, technology, artificial intelligence and medical equipment. S pace crafts A utomation circuits of robots Strategic plant temperature handlers CT scan for displaying the infected areas of body

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