Question

Which of the following nanomaterials has one dimension \(< 100\) nm?

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

Hint:

Count how many dimensions are confined below 100 nm: thin films are confined in one only.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
Nanomaterials are classified by how many of their dimensions fall in the nanoscale (below 100 nm). Zero-, one-, two- and three-dimensional confinement give different shapes.

Step 2: Classification
- Quantum dots are confined in all three dimensions, so all three are below 100 nm (zero-dimensional objects).
- Nanowires and nanorods have two dimensions (the cross-section) below 100 nm while the length is large.
- Nanorings are small closed loops with all dimensions in the nanometre range.
- Thin films have only the thickness below 100 nm, while length and width are large.

Step 3: Match the options
(A) Quantum dots: three nano dimensions. (B) Nanorings: all nano. (D) Nanowires: two nano dimensions. (C) Thin films: exactly one nano dimension, the thickness.

Step 4: Conclusion
The material with only one dimension below 100 nm is the thin film, option (C).

Final Answer:
A thin film is nanoscale only in its thickness, so the answer is option (C). \[ \boxed{\text{Thin films}} \]