【正文】
??????????????????????????1e x p 1e x p2TkeVJTkeVnNLeDNLeDJBsoBiaeedhht o t a lPrinciples of LEDs ( Light Emitting Diode, 發(fā)光二極管) (a) p n+ Eg eVo Electron in CB(導(dǎo)帶) Hole in VB(價帶) Ec Ev EF eVo Electron energy Distance into the device Ec Ev EF Spontaneous emission (自發(fā)發(fā)射) h u E c E v hv ? Eg Eg (b) V p n+ e(V0V) 正向偏置 Principles of PN photodetectors (光探測器) E v E c h u Absorption (吸收) p + SiO 2 Electrode (電極) R e h + I ph h u E g W E n Depletion region (耗盡區(qū)) ( a ) Antireflection Coating (減反膜) V r Electrode (電極) V out 反向偏置 E 1 E 2 h u Absorption (吸收) h u Spontaneous emission (自發(fā)發(fā)射) E 2 E 1 h u Stimulated emission (受激發(fā)射) In h u Out h u E 2 E 1 Three possible processes in photonelectron interactions ( hv = E2 E1 ) In stimulated emission, number of photons are amplified.