Question

Arrange the following structures in terms of increasing order of confinement: (A) Quantum Well, (B) Bulk Material, (C) Quantum Dot, (D) Carbon Nanotube

• A. (A), (B), (C), (D)
• B. (B), (A), (D), (C)
• C. (C), (B), (A), (D)
• D. (D), (B), (C), (A)

Hint:

Bulk materials have no confinement as the electron is free to move in all 3 dimensions, whereas quantum wells confine motion in 1 dimension, quantum wires confine motion in 2 dimensions and quantum dots confine motion in all 3 dimensions.

Answer 1

The Correct Option is B

Confinement in nanomaterials refers to the restriction of particle movement in one or more dimensions.
• Bulk Material: There is no confinement and particles have freedom of movement in all the dimensions.
• Quantum Well: The particles are confined in one dimension only.
• Carbon Nanotube: Particles are confined to two dimensions (moving along the tube).
• Quantum Dot: Particles are confined in all three dimensions leading to quantum confinement.
Therefore, the order of increasing confinement is Bulk material <Quantum well <Carbon nanotube <Quantum dot.