Quantum mechanics in electronics NOTE: To change the image on this slide, select the picture and delete it. Then click the Pictures icon in the placeholder to insert your own image. 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: QUANTIZATION OF CERTAIN PROPERTIES(CONJUGATE VARIABLES) QUANTUM ENTANGLEMENT PRINCIPLE OF UNCERTAINITY(HEISENBERG’S PRINCIPLE) WAVE PARTICLE DUALITY

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)

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)

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.

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 High speed computation 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.