Which of the following best describes the operation of a ...

[ss2343]

Which of the following best describes the operation of a photovoltaic (solar) cell?
  a. The operation of the solar cell does not depend on the light's wavelength.
  b. The best solar cells are not made from semiconductor materials.
  c. A solar cell acts like a LED operating in reverse.
  d. The solar cell is most similar to a npn or pnp transistor.
  e. Solar cells are limited to an efficiency of about 6.

Question 2

You are trying to build an n-type impurity semiconductor and know the properties of the silicon as well as the dopant. To make the semiconductor, you will use a dopant with
 

a. a Fermi energy near the valence band of silicon.
  b. a valence band just below the Fermi energy of silicon.
  c. a Fermi energy just above the Fermi energy of silicon.
  d. a conduction band just above the Fermi energy of silicon.
  e. a Fermi energy just below the conduction band of silicon.

[Bsand8]

Answer to Question 1

c.
The incoming photon promotes an electron from the valence band to the conduction band, resulting in the flow of electric current.

Answer to Question 2

e.
The Fermi energy of the dopant is the highest filled band, or the valence band. If this band was just below the conduction band of silicon, electrons from the dopant could easily be donated to the silicon to conduct electricity, making an n-type semiconductor.

[ss2343]

Excellent

[yeungji]

TYSM