Ms contacts - energy-band diagrams a number of ms contacts are formed on si substrates maintained at t = 300k. for each of the contacts listed below, draw the energy-band diagram (indicating the schottky-barrier height db, the depletion- layer width w, ec - ef in the neutral region, and the built-in potential v bi ), and indicate whether the contact is ohmic or rectifying: a) an ideal contact between al ((pm= 4.1ev) and n-type silicon with np = 1017 cm3, va= 0v b) an ideal contact between al (pm= 4.1ev) and p-type silicon with na = 1017 cm3, va= 0 v. c) an ideal contact between al (pm=4.1ev) and p-type silicon with na = 1017cm3, va= -0.5 v. d) a contact between nisi and n-type silicon with np = 1017 cm3, with va= 0 v. e) a contact between nisi and p-type silicon with na = 1017cm3, with va= 0 v. note: for the nisi contacts, use the schottky barrier values given in lecture notes

the plateau is likely to turn into a desert do to corrosion.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.

that would be because of both gravity and friction. so     c