{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

hw11_new - voltage At what forward voltage do the bands...

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

View Full Document Right Arrow Icon
ECE 440 Homework 11 Fall 2009 Due: Friday, Nov 20, 2009 1. Illuminated Diode. A silicon p-n diode with reverse saturation current 10 -10 A is used as photodiode. This diode is illuminated with sunlight, yielding a photocurrent of 1 mA. Find the maximum power (P m ) which can be generated by this diode (in the 4th quadrant, as in Fig. 8-3 of the textbook), and calculate the corresponding voltage (V m ) and current (I m ). 2. P-N junction Simulation. In the following exercise we will revisit the problem 3 of HW 10 and use the pn junction tools found in the following link: http://nanohub.org/resources/5120 Consider a Si sample maintained at equilibrium and room temperature with a p-side doping of N A = 10 17 /cm 3 and an n-side doping of N D = 5 × 10 17 /cm 3 . Keep all other parameters on the nanoHUB to their default values unless otherwise stated. I) Use the ‘PN Junction Exact Solution’ and view the Energy band diagram as a function of bias
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: voltage . At what forward voltage do the bands become flat? Plot the band diagram at V = 1 Volt, and explain the shape of the bands. II) For a long diode, the excess carrier concentration are given by equations (5-31a) and (5-31b) Use the ‘PN Junction Long Base Depletion Approximation’ and plot the peak of excess electron and hole concentration vs. V app . At what voltage do you begin to see high-level injection? III) Theoretical Exercise: a. Explain qualitatively how a forward bias across a pn junction reduces the width of the depletion region. b. For the pn junction considered in this problem, deep in the p-region is the current carried exclusively by electrons or holes? For such case, is the current dominated by drift, diffusion, or both? Justify your answer....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online