Question

Explain why you cannot see through silicon

Answer 1

There's 2 explanation for this question.Both of them are cited below

A solid material will appear transparent if there are no processes that compete with transmission, either by absorbing the light or by scattering it in other directions. In pure silicon, there is a very strong absorptive process at work: the incident visible light is absorbed by electrons that then move from one electron energy state to another .

As you an object is visible when only the light reflected from the object reaches our eyes.In this scenario the incident light is completely absorbed by the silicon crystal.so we cant see through silicon.

A material that appears homogeneous to the human eye is really made up of minute crystals--regions in which the atoms or molecules follow a regular order. The boundaries between these regions are called grain boundaries. If the distance between boundaries is smaller than the shortest wavelength of visible light (in other words, if the refractive index of the material is uniform with respect to the light passing through it), then the material will appear transparent. Each boundary tends to diffuse the light that passes through; if the regions are small enough, however, the light waves essentially 'jump' right over them.

Since silicon (sand) has obvious grain boundary it is not transparent.Given below is the picture of a polycrystal silicon.Grain boundaries and grains are marked respectively.Thank you