Download Quantum mechanics in electronics

QUANTUM MECHANICS
IN
ELECTRONICS
By
AKHIL SANJAYA KUMAR
ROLL NO 7
WHAT IS QUANTUM MECHANICS ?
 FUNDAMENTAL BRANCH OF PHYSICS- DEALING WITH PARTICLES OF VERY
SMALL SIZE (ATOMS, MOLECULES,SUBATOMS)
 ACCOUNTS THE 4 REASONS WHICH THE CLASSICAL MECHANICS FAIL:
1. QUANTIZATION OF CERTAIN PROPERTIES(CONJUGATE VARIABLES)
2. QUANTUM ENTANGLEMENT
3. PRINCIPLE OF UNCERTAINITY(HEISENBERG’S PRINCIPLE)
4. WAVE PARTICLE DUALITY
SOME MORE IMPORTANT CONCEPTS:
1. QUANTUM TUNNELLING
 In short an electron wave with less
potential crosses a barrier with larger
potential(explain)
2.
QUANTUM WELL
 The region between two barriers
containing some electrons of some
energy (usually for matching energies)
3. SPIN
 Electrons revolve around their axes
clockwise or anticlockwise(spin states)
SEMICONDUCTOR APPLICATIONS
 Presence of a quantum well of some
energy level between two insulator
barriers
 By adjusting the bias from the source
terminal ; if energy of the same level
provided (resonance with the well) the
electron wave passes through the
barriers
 The potential application of RTD’s is to
reduce the component count, area, and
power dissipation of conventional
transistor circuits by replacing some,
though not all, transistors.
Example :a pair of RTD’s and a transistor(forms a memory
 Comprises: a pair of conductive
wells and an insulator barrier
between
 Important point: electron wave will
pass through the barrier if energy
levels of the wells are equal
 Energy Levels of the two wells can
be varied using the top and the
optional bottom gates
 Experimental versions are produced
which work at 4.4, 77k and 273k
 Room temperature versions are
expected soon.
spintronics
• SPIN Transport electrONICS:
• Conventional electronics have digital states (0,1) depending on
whether the current is “on” or “off”(flowing)
• Electrons have 2 spins states which can also be used as the
digital states
• Why used? When size of the devices are reduced to such a small
extent that the leakage power becomes detrimental; spintronics
based devices can be used where power dissipation is negligible
• Not widely applicable: Difficulty to generate, control and sense
the electron spin
QUANTUM COMPUTERS
• General Description: an
abstract machine to model
the effect of quantum
computation
• Unlike digital electronics,
Q-Computers use Q-bits
which occupies the value 0,
1 or both simultaneously
• Concepts used :
entanglement ,
superposition
QUANTUM COMPUTERS(CONTD.)
 ANALOGY:
 To solve optimization problems(landscape with valleys and
tops)
 Altitude corresponds to energy level
 Comparison with a normal computer for solving these
problems
 Advantages
1. High speed computation
2. Large no of answers in short time
conclusion
Quantum mechanics is the science of the
very small. Quantum mechanics explains
the behaviour of matter and its interactions
with energy on the scale of atoms and
subatomic particles.
We can see that quantum concepts have
wide range of applications in different types
of diodes, even computers as well as other
devices like the Josephson junction and
MRI. 15, no in 10 year’s time we can expect
even further breakthrough in the
semiconductor technology and see the
growth of quantum computers which may
later run our life itself.