{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Hw3 - 3 Calculate the approximate band gap of Si from Eq...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 340 Homework III Fall 2005 Due: Monday, September 12, 2005 1. In practice we assume that the intrinsic Fermi level, E i , coincides with the center of the band gap. In reality it is not true. Derive an expression relating the intrinsic level E i to the center of the band gap. Find the displacement of E i from the center of the band gap for both silicon and germanium at room temperature. The effective mass values are m n * = 0.55 m o for Ge and 1.1 m o for Si; m p * = 0.37 m o for Ge and 0.56m o for Si where m o is the free electron mass. 2. Math exercise: plot the function f(x)=exp(3x) from x=0.01 to 2.0 in two graphs. One is on a linear scale and the other on semi-logarithmic scale.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 3. Calculate the approximate band gap of Si from Eq. 3-23 and the plot of n i vs. 1/T (Fig. 3-17). Why is it moderately different from the measured 1.1 eV at room temperature? 4. The hole concentration in a silicon material is 4x10 5 /cm 3 at room temperature under equilibrium conditions. (a) What is the electron concentration? (b) Where is E F positioned relative to E i ? (c) Draw the energy band diagram for the material. Repeat for parts (a), (b) and (c) for the same sample if the temperature is 400 K. Refer to Fig. 3-17 to obtain the intrinsic carrier concentration at 400 K. Also, the band gap energy is reduced to 1.08 eV at 400 K....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online