M.Sc. Physics(Material Science) (Semester IV)
(CGPA) Examination, 2017
NANO SCIENCE AND NANO TECHNOLOGY
Day Date: Saturday, 29-04-2017 Max. Marks: 70
Time: 02.30 PM to 05.00 PM
Instructions and are compulsory.
Answer any three questions from Q.3 to Q.7.
All questions carry equal marks.
Q.1 Objective questions: 08
If an electron is confined in limited space then the allowed
energy states are.
Continuous Discrete Limited None
In bottom up approach the building blocks can be.
Atoms Molecules Clusters All above
If the size of the metal nanoparticles decreases then the
position of the SPR peak.
Shift towards lower wavelength
Shift towards higher wavelength
Remains same
None of these
For emission of the electrons from the metal surface the
minimum required energy is.
Work function of the metal
Binding energy of the electron
Kinetic energy of the electron
None of these
The basic principle of AFM is.
Change in force due to change in distance
Change in current due to change in distance
Change in shape due to change in distance
Change in size due to change in distance
In SEM the morphology of the sample is achieved with the help
of.
Secondary electrons Primary electrons
Emitted electrons Photo electrons
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Nanotubes usually form in bundles. Which is the best
description of such a bundle?
The tubes are aligned, axes parallel, with van der Waals
forces operating between adjacent tubes.
The tubes are connected together by covalent C-C bonds.
The tubes are randomly organized, with the axes of the
tubes lying in random directions
The bundles of discrete sizes, and dipole-dipole forces hold
the tubes together
The surface area to volume ratio of a sphere with radius 30 nm
is.
108 109 107 106
State True or False/ Fill in the blanks: 06
The band gap of semiconductor nanoparticles decreases with
increase in size.
The SPR observed for insulator nanoparticles.
STM can be used for conducting as well as insulating samples.
The Drude model neglects any long-range interaction between
the electron and the ions or between the electrons.
The electron mobility in semiconductors can be greatly
decreased by the formation of polarons.
The ball milling is a top down method.
Q.2 Write short notes: 14
Quantum confinement effect 05
Electron transport in semiconductors 05
Single electron transistor 04
Q.3 How do you expect the conductivity to vary in an intrinsic
semiconductor with increasing temperature?
07
How do you expect the conductivity to vary in a metallic conductor
with increasing temperature?
07
Q.4 "Template-assisted synthesis is a very efficient tool to grow highly
ordered and nano-wires/rods" Explain.
10
Explain in brief the basic process of VLS technique. 04
Q.5 Describe principle and operation of TEM. 10
Explain how a CNT can be bent to a ring. 04
Q.6 "Bottom-up technique is more convenient for nano fabrication"
Explain.
10
Why is spatial resolution of STM better than AFM? 04
Q.7 Explain how endo-fullerenes can be used as one-dimensional
metal-semiconductor junctions?
10
Explain the basic difference between a PVD and CVD process. 04