Quantum Dot Emission: Band Gap & Heisenberg's Uncertainty

  • Context: High School 
  • Thread starter Thread starter bluejay27
  • Start date Start date
  • Tags Tags
    Dot Emission Quantum
Click For Summary
SUMMARY

The discussion centers on the relationship between quantum dot size and band gap, highlighting that as quantum dots decrease in size, their band gap increases due to quantum confinement effects. This phenomenon is explained through the analogy of the particle-in-a-box model, where energy spacing increases as the box size diminishes. The quantum confinement effect becomes significant when the dot size approaches the thermal deBroglie wavelength of an electron, making it observable even at room temperature, particularly in Cadmium Sulfide quantum dots.

PREREQUISITES
  • Understanding of quantum mechanics principles, specifically the Heisenberg's uncertainty principle
  • Familiarity with quantum dot technology and its applications
  • Knowledge of the particle-in-a-box model in quantum physics
  • Experience with analyzing absorption and emission spectra
NEXT STEPS
  • Research the quantum confinement effect in various semiconductor materials
  • Explore the thermal deBroglie wavelength and its implications in quantum systems
  • Study the properties and applications of Cadmium Sulfide quantum dots
  • Learn about advanced spectroscopy techniques for analyzing quantum dot emissions
USEFUL FOR

Researchers in quantum physics, materials scientists, and engineers working with semiconductor technologies, particularly those focused on quantum dot applications and their optical properties.

bluejay27
Messages
67
Reaction score
3
Why does the quantum dot's band gap increase as in shrinks in size? What is the principle behind this? Is the Heisenberg's uncertainty principle?
 
Physics news on Phys.org
The short answer is that the bandgap increases for the same reason that the energy spacing for the particle-in-a-box increases as the box size gets smaller.

This quantum confinement effect becomes resolvable when when the size of the dot approaches the thermal deBroglie wavelength of an electron in the dot. So, at low temperatures, the effect of quantum confinement can be seen in slightly larger dots, but the phenomenon is perfectly visible at room temperature. As an undergrad, I looked at the absorption and emission spectra of Cadmium Sulfide quantum dots as a function of size, and we could clearly see the effect at room temperature.
 

Similar threads

High School Can Visible Light Excite Quantum Dots to Emit Fluorescence?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Why diode with larger band gap has larger onset potential?
  • · Replies 7 ·
Replies
7
Views
4K
Undergrad How Do Quantum Dots Emit UV Light?
  • · Replies 6 ·
Replies
6
Views
2K
High School What Does Not Allowed in Quantum Theory Mean Regarding Band Gaps?
  • · Replies 1 ·
Replies
1
Views
4K
High School Is the Heisenberg Uncertainty Principle a result of measurement inadequacies?
  • · Replies 13 ·
Replies
13
Views
2K
Undergrad Heisenberg Uncertainty Principle Violation?
  • · Replies 23 ·
Replies
23
Views
5K
Graduate Analyzing GaAs Quantum Wells Emission Spectrum
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Question: Quantum Dot Laser - Energy Band
  • · Replies 2 ·
Replies
2
Views
3K
How Does Voltage Affect LED Color Through Band Gap Adjustments?
  • · Replies 1 ·
Replies
1
Views
1K
Graduate Probability of photon emission from quantum dot
  • · Replies 12 ·
Replies
12
Views
3K