RGPV Exam Papers BE Nano Electronics 8th Sem June 2012

RGPV Exam Papers BE

Nano Electronics 8th Sem June 2012

Note : Attempt any five questions. All questions carry equal marks.

Q.1 (a) Discuss the ‘top down’ and ‘bottom up’ approaches of nanotechnology.

Why is nano electronics needed ?

(b) Qualitatively discuss the analogy between extrinsic semiconductor and the intrinsic semiconductor with suitable examples.

Q.2 (a) How does conduction take place in insulators and

ionic crystals ? Also discuss the electron transport in semiconductors.

(b) Discuss various conduction mechanics in 3 D and 2 D and low dimensional systems.

Q.3 (a) Discuvs the concept of scanning tunnelling microscope

and atomic force microscope.

(b) Obtain expressions for tunnelling currents.

Q.4 (a) Describe the concepts of quantum wells, wires and dots.

(b) Draw and discuss schematic structure of a metallic single electron transistor.

Q.5 (a) What do you understand by molceular machine and nanobiometrics ?

(b) Describe the basic structure of carbon nanotubes.

Q.6 (a) State and explain the basic difference between the Thermionic and Schottky emission.

(b) Show that the product of number of holes in the valence band and the number of electrons in the conduction band depends only on temperature and band gap Also show that conductivity a of an intrinsic semiconductor can be used to measure the band gap by calculating In u.

Q.7 (a) Why is the wave nature of matter not apparent to us in our daily observations ?

(b) Discuss the chemical vapour deposition method to produce high purity and high performance solid materials.

Q. 8 Write short notes on any two of the following :

Photolithography

Plasma arc discharge

Pulsed laser deposition

Molccular beam epitaxy

 

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