How many micrometer of penetration depth of light inside materials and factors affect it?
Dear Mosaad,
the propagation of light intensity in matter is described by the Lambert -Beer law (also called Beer-Lambert law):
I(x) = Io*exp(-µ*x);
with Io as primary photon flux penetrating into the material
(intensity loss due to reflection is already considered),
I(x) as the photon flux at depth x
and µ = µ(M,E/lamba) as the attenuation coefficient, which depends on the material M itself, the photon energy E (or wave length lambda) of the light.
The Lambert Beer law is an exponential equation, which shows that in principle the light is able to travel up to infinite depths.
The penetration depth is by convention chosen as the mean travelling distance of the light.
So we have: penetration depth dp = mean travelling distance = 1/µ . (Please note that 1/µ has the dimension of a length.)
So for the distance x at x = dp = 1/µ
we have I/Io = exp(-µ*1/µ) = exp(-1) = 1/e ~36,7%.
'factors affecting it': The attenuation coeffcient includes photon absorption and photon scattering.
For details please google for 'attenuation coefficient'.
So now it is up to you to search the appropriate attenuation coefficient for your wave length of light and your material and calculate 1/µ. (....and convert that number into the right unit (µm) as you requested; µ is often given in 1/cm thus 1/µ then is in cm; but pay attention on the unit of µ of your source).
https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law
Sorry, but I won't irritate you.
But nevertheless please specify wavelength and material and we can figure out that number.
Best regards
It depends on absorption coefficient of the semiconductor, if the absorption coefficient is higher, thickness of 500 nm can absorb the most of light irradiation and it depends on semiconductor properties.
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