optical processes in semiconductors: review a. aydınlı

Optical Processes in Semiconductors: Review

A. Aydınlı

PL Emission of optical radiation

resulting from excitation to a nonequilibrium state by irradiation with light. Create electron-hole pairs by

absorption of exciting light Radiative recombination of electron-

hole pairs Escape of recombination radiation from

the sample.

PL

Sensitive (compared to absorption) Nondestructive Simple to perform Considerable analysis may be

required to reach the physical mechanism

Electron-Photon Interaction

Solve:

To obtain:

)()(2

1 2

0

rVeApm

H

0

22

00

2

2)(

2)(

2 m

AepAAp

m

erV

m

pH

)()(2 2'

ababs EEarHbW

pAm

eH

0

')(

2 0

2

rVm

pH

Fermi’s Golden Rule Interaction energy between the radiation field

and atomic system can be written either

222 )2/()/( jj

j AmcepAmceH

jj reEHor

Absorption/Emission

DOS

Transitions in Bulk

Emission vs Gain

Direct Gap Absorption

Direct Gap Absorption

Absorption in QW

Population Inversion in a QW

Intersubband Absorption

Intersubband Absorption

Inter- and intraimpurity Transitions

Free-bound:

Band-band:

Degeneracy: