EE 305 HW#4b

# EE 305 HW#4b - illumination of a semiconductor are...

This preview shows pages 1–2. Sign up to view the full content.

ECE 305 Homework #4 Due Wednesday, February 17 Problem 1: At x = 0, the injector maintains a steady state excess hole concentration of p(0) = 10 10 cm -3 and the extractor at x = 10 -6 cm maintains p(10 -6 cm) = 0. a) Do low level injection condition exist throughout the semiconductor? Why or why not? b) You can ignore recombination in the semiconductor, which means every injected hole at x = 0 makes it to x = 10 -6 cm. How can you deduce that? c) Find an expression for p(x) in the semiconductor. d) Is there a hole current? If so, what is it? Problem 2: (see fig on next page). The equilibrium and steady state conditions before and after

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: illumination of a semiconductor are characterized by the energy band diagrams shown below. For this semiconductor at T = 300 K, n 1 = 10 9 cm-3 , μ p = 500 cm 2 Vs , and μ n = 5000 cm 2 Vs . a) Determinen o and p o the equilibrium carrier concentrations. b) Determine n and p under steady state conditions. c) What is N A ? d) Do we have low-level injection when the semiconductor is illuminated? Explain. e) What is the resistivity of the semiconductor before and after illumination? 10-6 cm x (cm) n o = 10 17 cm-3 p o = 10-3 cm-3 Lp = 10-4 cm injector extractor...
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

EE 305 HW#4b - illumination of a semiconductor are...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online