All Questions
Tagged with optical-materials semiconductor-physics
9 questions
5
votes
2
answers
1k
views
Why are there direct bandgaps?
This Question has been bugging me for sometime. Some semiconductors have direct bandgaps and indirect bandgaps. So what causes a direct bandgap to occur? The physics behind ,why there are direct ...
- 520
2
votes
1
answer
448
views
Why is GaN better than Si as a substrate for ZnO thin film?
in an attempt to grow a thin film using ZnO, I found many researches use silicon as a substrate and others use GaN. by further research I found that GaN is preferred than silicon but I don't know the ...
- 41
2
votes
1
answer
154
views
How to control the refractive index of semiconductors?
I keep seeing/hearing that the refractive index can be controlled in semiconductors, but every time I read something like that it's always something very specific, like "Refractive index ...
1
vote
0
answers
359
views
Change of refractive index using semiconductor
I was wondering, if it is possible to change the refractive index of a semiconductor using an electric field or current? I have heard about injecting charges to tune the refractive index. How/Why does ...
- 839
0
votes
1
answer
347
views
Does crystalline silicon have a higher (~3.0 eV) band gap than amorphous Si (~1.75 eV)? Or lower (~1.12 eV)? [closed]
Some sites claim that crystalline silicon has a band gap of approximately $1$ to $1.2$ or so electron volts, and others say it is about $3$ to $3.4$ eV....
Amorphous silicon is usually described as ...
- 4,709
0
votes
1
answer
122
views
Why can you not create a LED equivalent by illuminating a colored plastic casing?
I would first like to apologize if this is a dumb question.
I understand the physics of color sufficiently well. You have an incoming photon that intercepts an electron on the atom, the electron gets ...
- 165
0
votes
1
answer
176
views
What is a pump reflector?
I understand the meaning of laser pumping. But i don't understand what is a pump reflector. As a clear definition does not appear online.
In the paper,DESIGN AND DEVELOPMENT OF WIDEBAND HYBRID RAMAN/...
- 115
0
votes
1
answer
30
views
$\rm InP$ Mach-Zender modulator
I know how a Mach-Zender electro-optical modulator (MZM) works when based on non-linear crystals like LN. On-chip realization of MZMs is often done with $\rm InP$ that is a semiconductor. What is the ...
- 131
0
votes
1
answer
78
views
Can paint on a wall considered to be a thin film?
In know that general thin films are as thin as few microns to nanometres and have technical and optical uses. But can a dry paint on wall be considered the simplest example of thin films? I mean its a ...
- 49