Unformatted text preview: 2 2s 2 3p 2 for Carbon. 5. Calculate the number of states Z c (E) with energy equal to or less than .05 eV above E c in the conduction band. Take the effective mass of the electron to be 0.29m and not varying in this range of energy values. 6. Derive the expression for the location of E i in the band gap (given on page 20 in the handouts of class 8, 7. A piece of silicon contains 4 x 10 16 cm-3 phosphorous atoms as impurities and assume they are all ionized at room temperature. Taking n i as 10 x 10 10 cm-3 , what are the type and density of majority and minority carriers? 8. A n-type silicon with 10 15 cm-3 donor atoms is exposed to a stream of boron atoms at high temperature so that the borom atoms will diffuse throughout the sample of silicon and make the density of boron atoms to be 10 16 cm-3 . What is the net impurity and type of silicon?...
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- Spring '08
- Atom, Condensed matter physics, effective mass