09 - Drift and Diffusion

09 - Drift and Diffusion - EECS 320 Drift and Diffusion...

Info iconThis preview shows pages 1–4. 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

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: EECS 320 Drift and Diffusion Current J. Phillips EECS 320 Thermal Motion Of Carriers Electrons move randomly in crystal with zero net displacement This is the thermal motion of carriers V th typically ~10 7 cm/s for most semiconductors! J. Phillips EECS 320 Application Of Electric Field Electrons/holes respond to electric field = drift v * m qE v drift = Note that carriers are in motion without electric field (thermal energy) Carriers are accelerated by electric field Carriers scatter from crystal imperfections Average velocity obtained between scattering (vdrift) J. Phillips EECS 320 Drift Current Drift current due to electrons and holes E E J drift = = JA EL A L I V R = = = ) ( ) ( ) ( drift p drift n drift J J J + = J. Phillips EECS 320 Conductivity and Mobility Define mobility: proportionality between v drift and E, represents carrier scattering dp dn drift qpv qnv E J + = = E qpv qnv dp dn + = E v dn n = E v dp p = Conductivity depends on both carrier density and mobility p n qp qn + =...
View Full Document

Page1 / 9

09 - Drift and Diffusion - EECS 320 Drift and Diffusion...

This preview shows document pages 1 - 4. Sign up to view the full document.

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