Germanium has a bandgap of 0.66 ev. the temperature is 25 degree celcius. (i) assuming that the material is intrinsic and that b is 2.31 e + 30 k-3cm-6, calculate the hole density. (ii) what is the dopant concentration that you would use if germanium has to have an electron concentration of 5.0e + 17 cm-3. (iii)give an example of a dopant atom that you would achieve to an electron concentration of 5.0e + 17 cm in germanium. give a clear reason for your choice considering that the material is germanium. (iv)draw the conduction band, valence band and the energy level of the dopant atom used to achieve the above electron concentration. you only need to draw the energy level of a single dopant atom. (v) what is the charge at each dopant atom location?

an energy transformation flow diagram is shown

where is it ?

small = small current large mag large current

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.