{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

ece340Fall03HW5sol

# ece340Fall03HW5sol - ECE 340 Homework V Fall 2003 Due...

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

ECE 340 Homework V Fall 2003 Due: Wednesday, September 24, 2003 Solution: 30 points total 1. An p-type Si sample with N a = 2x10 16 /cm 3 is steadily illuminated such that g op = 10 21 EHP/cm 3 -s. If τ n = τ p =1 μs for the excitation, calculate the separation in the quasi-Fermi levels, (F n -F p ). Draw a band diagram such as Fig. 4-11. Solution: (a) 15 3 1 10 op n p g cm δ δ τ = = = × , therefore indeed low level injection 15 3 0 1 10 n n n cm δ = + = × 16 3 0 2.1 10 p p p cm δ = + = × 0.0259ln 0.288 n i i n F E eV n = = 0.0259ln 0.366 i p i p E F eV n = = 0.654 n p F F eV = 2. (a) A Ge bar 0.1 cm long and 100 μm 2 in cross-sectional area is doped with 1x10 17 /cm 3 gallium. Find the current at 300 K with 10 V applied. Repeat for a Ge bar 1 μm long assuming that the saturation thermal velocity of electrons in Ge is about 10 7 cm/s. (b) Upon a steady illumination uniform excess carriers are generated in the Ge bar. Assume that τ n = τ p = 1 μs for the excitation. Estimate the optical generation rate of EHPs per second required to increase the current by 10% in part (a).

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.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern