Essay on Preparation of Semiconducting Thin Films

992 Words Sep 27th, 2008 4 Pages
Abstract:

One is to determine the gap energy of cadmium sulfide semiconductor thin film using the equation: Eg = h.c/ is the signal of the long wavelength limit of the absorption peaks (measured in the lab). The reaction between cadmium sulfide and NH3, in the presents of thiourea yield a  of 579(nm). The % error of the reaction is 1.24%.

Introduction:

There are 3 types of metals for electricity conducting: metallic conductor, semiconductor, and superconductor. Metallic conductors allow the free flow of ions and electrons through a sample; and its conductivity decreases as the temperature increases.
Semiconductors allow the flow of both ions and electrons through the sample but not completely free; and its
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What are n- and p-type conductors? What’s meant by doping?

n-type conductors:
When an external (excess of electrons) atom is added to the pure semiconductor, this will result in increase in conductivity of the semiconductor and will result in the n-type semiconductor. The reason for that is the semiconductor’s valance band is fully filled with electrons and the conduction one is partially filled. The addition will allow the donor band’s electrons to jump and fill the conduction band resulting in a decrease in the band gap. In sum, the n-type semiconductors are solids doped with atoms that supply electrons to the conduction band.

p-type:
When external atoms (less than 2n electrons) are added to a pure semiconductor, this will result in an accepter band (empty band) near the valance band. The accepter band will decrease the gap band. This will lead the electrons from the valance band to the accepter band, creating positive spots in the valance one. The positive spots with let the electrons move more freely in the valance band, which will increase the conductivity of the pure semiconductor. In sum, the p-type semiconductors are solids doped with atoms that remove electrons from the valence band.

Doping: additional external electrons carriers which will increase the conductivity of a pure semiconductor. Conclusion:

The transition of electrons from the

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