Light-Matter Interaction

Question 1

What are the two types of Electron-Hole pairs in light-matter interactions, and what do they do? ***

Answer 1

1) Recombination → Produces Light ***

2) Generation → Cause by incident light promotes electrons ***

Question 2

What does the P-N Junction do in Recombination?

Answer 2

• Current can produce Light to → Light Emitting Diode (LED)
• Higher to Low Photon

Question 3

What does the P-N Junction do in Generation?

Hint: E-H pairs

Answer 3

• Electron-Hole pairs can be seperated into → Current into → Photodectors

Question 4

In Phonon Dispersion, what does the (ω) stand for?

Answer 4

ω → Scattering Angular Frequency

Remember: Also ω - Angular Velocity

Question 5

In Phonon Dispersion, k = 2π/λ. What does is stand for?

Answer 5

k = 2π/λ → Scattering Magnitude

Question 6

In a Phonon Dispersion Graph, when the slope is near k = 0, what does this represent?

Answer 6

Lower Branch = Speed Of Sound (Acoustic)

Question 7

In a Phonon Dispersion Graph, when the slope is near k = ±π/a, what does this represent? **

Answer 7

Slope near k = ±π/a → Standing Waves **

Question 8

In a Phonon Dispersion Graph, Heat Capacity can be calculated by using 2 curves, a red and blue curve. What do these represent?

Answer 8

Blue Curve (Optical) = Speed Of Light

Red Curve (Acoustic) = Speed Of Sound

Question 9

When photons are released they go from ….

Answer 9

Photons released go from Conduction band to → Valence band

Question 10

When photons are absorbed they go from….

Answer 10

Photons absorbed go from Valence band to → Conduction band