# Nano electronics

## Why energy discreteness occurs in nano materials ?

Ans. The effects of supplementary discreteness of nanostructural process kinetics are caused by the presence in the field plasma systems of temporary lived compound quantum particles-compactons (swarming electron pairs, . electrons together with antielectrons, ternaries, tetrads of them and so on) along with elementary [...]

## What are excitons ? Also give their type.

Ans. The excitons are defined as the bound states of photo-excited and Coulomb-correlated electron-hole pairs, produced momentarily by light Incident Photon illumination of energy greater than the band gap of the material concerned. The electron-hole pairs, thus produced, will orbit around each other, having equal [...]

## Write down the Schrodinger equation as the – (i) Electron trapped in 2D plane nanosheet (ii) Electron moving ill one-dimension/ nanowire.

Ans. (i) Electron Trapped in 2D Plane Nanosheet - When carriers are confined in one dimension, i.e., along-direction to a very small thickness t, and free to move along X and Y -direction. In nanophysics, it is the case of nanosheets where carriers are [...]

## Write down the application of Schrodinger equation when a particle is trapped in 3D potential box.

Ans. Assume that a particle inside a 3D infinite trap volume L3 with impenetrable walls as shown in fig. 1.36. Then the generalized Schrodinger equation in three dimensional is given as- Nanoparticles with a fraction of a nanometer to a few tens of nanometers size can be [...]

## How the tunneling can be achieved through penetration of barrier?

Ans. If the width of the step potential becomes finite say, the potential step extends from x = 0 to x = d, i.e., the thickness of the potential barrier is d, then we will get the tunneling phenomenon of barrier penetration also called 'quantum leak'. [...]

## Explain the quantum leak by reflection and tunneling effect. Or Write down the application of Schrodinger wave equation in quantum leak.

Ans. Assume that a particle moving along positive x-axis towards a finite potential step as shown in fig. 1.33. here, V = 0 for x <0         Region-I V = V0 for x >0                  Region-II   Case I : E > Vo- If the incoming x=O X particle has [...]

## Write down the application of time independent Schrodinger wave equation to particle trapped in a one dimensional square potential well.

Ans. Assume, a particle is trapped in 1D according to the following potential distribution - finite inside the well. Hence the Schrodinger equation becomes -                                       ....(ii) The general solution of this second-order linear differential equation will be where, A 1 = 2iA, called the normalization constant and can [...]

## Derive Schrodinger wave conversions.

Ans- erwin Schrodinger given the equation of the wave function (x, t), describing the location of a particle in a given physical situation. this equation is formulated on the following Basis-

## Define Heisenberg uncertainty principle and give formula for group velocity.

Ans. Heisenberg Uncertainty Principle - It states that the position x, und momentum p, of a particle can be measured simultaneously only to minimum levels of uncertainty,  and  respectively, such that -

## Explain the wave function associated with an electron.

Ans. According to de-Broglie's concept of matter wave, every moving particle of matter is associated with a wave. Schrodinger introduced a mathematical function represent by IJI which is a variable quantity associated with a moving particle, and is a complex function of the space, coordinates of the particle [...]

## Discuss de-Broglie theory of matter waves. How is the existence of these waves experimentally verified ?

Ans. With the discovery of an electron as a fundamental particle by J.J. Thomson in 1897, most of the studies in physics concentrated to explore microscopic ·or atomic systems which are beyond the scope of direct observations. Many difficulties were encountered with phenomena which are spectral distribution of [...]

## Write short note on DNA computing.

Ans. DNA computing is a very interesting field in nanobiotechnology. It is a nanocomputer that uses DNA to store information and perform complex calculations. It is a programmable molecular computing machine composed of enzymes and DNA molecules instead of silicon microchips . .The computer could [...]