1. Quantum mechanics in electronics
NOTE:
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AKHIL SANJAYA KUMAR
ROLL NO 7

2. 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:
QUANTIZATION OF CERTAIN PROPERTIES(CONJUGATE VARIABLES)
QUANTUM ENTANGLEMENT
PRINCIPLE OF UNCERTAINITY(HEISENBERG’S PRINCIPLE)
WAVE PARTICLE DUALITY

3. SOME MORE IMPORTANT CONCEPTS:
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)
SPIN
Electrons revolve around their axes clockwise or anticlockwise(spin states)

4. SEMICONDUCTOR APPLICATIONS
RTD
RESONANT TUNNELLING DIODE
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 cell)

5. DELTT : DOUBLE LAYER TUNNELLING TRANSISTOR
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.

6. 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

7. 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

8. 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
High speed computation
Large no of answers in short time

9. 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.