10hw - Solutions to problem set 10 (141A Sp07) 1 1. (ISSP...

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

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Solutions to problem set 10 (141A Sp07) 1 1. (ISSP 8.1). (a) ISSP, page 210, equation (51): E d = 13 . 6 2 m e m eV = 13 . 6 18 2 . 015 eV = 6 . 3 10- 4 eV (b) ISSP, page 210, equation (52): a = . 53 m e / m = (0 . 53)18 . 015 = 636 (c) The wavefunctions of the impurity electrons need to overlap if they are to form a band: then the density needs to be at least one electron per (636) 3 , ie n = 1 (636) 3 = 1 . 6 10 7 m- 3 2. (ISSP 8.2). (a) ISSP, page 213, equation (53), n = n o n d e- E g / (2 k B T ) with n = 2 mk B T 2 ~ 2 ! 3 / 2 = 2 (0 . 01)(9 . 1 10- 31 )(1 . 38 10- 23 )4 2 (1 . 05 10- 34 ) 2 ! 3 / 2 = 3 . 9 10 19 m- 3 = 3 . 9 10 13 cm- 3 and so n n d = 3 . 9 10 26 = 1 . 97 10 13 cm- 3 . Also, since 4 K corresponds to 0 . 345 10- 3 eV , we have n = (1 . 97 10 13 cm- 3 ) e- 1 / (2(0 . 345)) = 4 . 6 10 12 cm- 3 (b) In SI units, R H = 1 / ne = 1 (4 . 6 10 18 )(1 . 6 10- 19 ) = 1 . 3 m 3 / C 3. (ISSP 8.3). Recall that j x = xx E x + xy E y j y = yx E x + yy E y Since the transverse current must be zero, E x =- yy...
View Full Document

Page1 / 3

10hw - Solutions to problem set 10 (141A Sp07) 1 1. (ISSP...

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

View Full Document Right Arrow Icon
Ask a homework question - tutors are online