Question

Which from following is an example of two dimensional nanostructures?

• A. Nanoparticles
• B. Thin films
• C. Quantum dots
• D. Nanowires

Hint:

Nanostructures are classified by the number of dimensions confined to the nanoscale (typically 1-100 nm). 0D for all dimensions (quantum dots, nanoparticles), 1D for two dimensions (nanowires, nanotubes), 2D for one dimension (thin films, graphene), and 3D for bulk materials (not confined in any dimension at nanoscale).

Answer 1

The Correct Option is A

Concept:
Nanostructures are classified according to how many dimensions lie in the nanoscale range (approximately $1$ nm to $100$ nm).

• 0D nanostructure: All three dimensions are nanosized
• 1D nanostructure: Two dimensions nanosized, one dimension larger
• 2D nanostructure: One dimension nanosized, two dimensions larger
• 3D nanostructure: Bulk materials made from nanoscale units

Step 1: Check Option A: Nanoparticles
Nanoparticles have nanoscale length, width, and height. \[ \Rightarrow \text{0D nanostructure} \] So, this is not two-dimensional.
Step 2: Check Option B: Thin films
Thin films have:

• Length = large
• Width = large
• Thickness = nanoscale

Only one dimension is nanosized. \[ \Rightarrow \text{2D nanostructure} \]
Step 3: Check Option C: Quantum dots
Quantum dots are nanosized in all three dimensions. \[ \Rightarrow \text{0D nanostructure} \]
Step 4: Check Option D: Nanowires
Nanowires have nanoscale diameter but long length. \[ \Rightarrow \text{1D nanostructure} \]
Step 5: Final Answer
The example of a two-dimensional nanostructure is: \[ \boxed{\text{Thin films \] Quick Tip:
Thin film = very small thickness but large surface area, so it is classified as 2D nanomaterial.