Why is the absorption depth for GaAs more than for Germanium?

  • Context: Undergrad 
  • Thread starter Thread starter A Sofyan
  • Start date Start date
  • Tags Tags
    Absorption Depth
Click For Summary
SUMMARY

The absorption depth for Gallium Arsenide (GaAs) is greater than for Germanium (Ge) due to the edge coefficients obtained at specific wavelengths. At 1550 nm, Ge has an edge coefficient of 459.54 / cm, while GaAs has a coefficient of 239.78 / cm at 885.6 nm. This indicates that the optimal thickness of GaAs is thicker than that of Ge, which raises questions about the transmissive properties of both materials at these wavelengths. The discussion highlights the transition of both materials from opacity to transmissivity around 1550 nm.

PREREQUISITES
  • Understanding of optical properties of semiconductors
  • Familiarity with absorption coefficients and edge coefficients
  • Knowledge of wavelength-specific material behavior
  • Basic concepts of material science related to GaAs and Ge
NEXT STEPS
  • Research the optical absorption properties of GaAs and Ge at various wavelengths
  • Study the theory of absorption depth and its implications in semiconductor applications
  • Examine the transition of materials from opaque to transmissive states
  • Explore practical applications of GaAs and Ge in photonics and optoelectronics
USEFUL FOR

Material scientists, optical engineers, and researchers in semiconductor technology will benefit from this discussion, particularly those focused on the optical properties and applications of GaAs and Ge.

A Sofyan
It is based on the value of the edge coefficient I obtained, for Germanium at the wavelength of 1550 nm has a value of 459.54 / cm and GaAs at wavelength 885.6 nm has a value of 239.78 / cm.

If based on the theory of absorption depth (1 / alpha), then the optimal thickness of GaAs is thicker than Ge, and to my knowledge, this seems to be wrong in the application, can anyone explain? Is there something wrong with my understanding?
 
Physics news on Phys.org
Both materials, if I'm not mistaken, are in a transition from being opaque at shorter wavelengths to starting to become transmissive at 1550 nm. Is there any reason you think Ge should be more transmissive than GaAs at this particular wavelength?
 
Charles Link said:
Both materials, if I'm not mistaken, are in a transition from being opaque at shorter wavelengths to starting to become transmissive at 1550 nm. Is there any reason you think Ge should be more transmissive than GaAs at this particular wavelength?
It is based on the value of the edge coefficient I obtained, for Germanium at the wavelength of 1550 nm has a value of 459.54 / cm and GaAs at wavelength 885.6 nm has a value of 239.78 / cm.
 

Similar threads

Undergrad Absorption cross section of light in air
  • · Replies 3 ·
Replies
3
Views
3K
Surface roughness in 2D sinusoidal corrugation
  • · Replies 1 ·
Replies
1
Views
5K
Graduate Even more light, a second kind.
  • · Replies 2 ·
Replies
2
Views
5K