Cov duab thaij thiab cov wavelengths txiav tawm

Photodetectorsthiab cov wavelengths txiav tawm

Tsab xov xwm no tsom mus rau cov ntaub ntawv thiab cov hauv paus ntsiab lus ua haujlwm ntawm cov photodetectors (tshwj xeeb tshaj yog cov txheej txheem teb raws li kev tshawb fawb band), nrog rau cov kev cai tseem ceeb thiab cov xwm txheej siv ntawm cov ntaub ntawv semiconductor sib txawv.
1. Lub hauv paus ntsiab lus: Lub photodetector ua haujlwm raws li qhov cuam tshuam photoelectric. Cov photons tshwm sim yuav tsum nqa lub zog txaus (ntau dua li qhov dav bandgap Eg ntawm cov khoom) kom txhawb cov electrons los ntawm valence band mus rau conduction band, tsim cov teeb liab hluav taws xob uas pom tau. Lub zog photon yog inversely proportional rau wavelength, yog li lub detector muaj "cut-off wavelength" (λ c) - qhov siab tshaj plaws wavelength uas tuaj yeem teb, dhau qhov uas nws tsis tuaj yeem teb tau zoo. Qhov cutoff wavelength tuaj yeem kwv yees siv cov mis λ c ≈ 1240 / Eg (nm), qhov twg Eg ntsuas hauv eV.
2. Cov ntaub ntawv tseem ceeb ntawm semiconductor thiab lawv cov yam ntxwv:
Silicon (Si): qhov dav ntawm bandgap yog li 1.12 eV, qhov cutoff wavelength yog li 1107 nm. Haum rau kev nrhiav pom wavelength luv luv xws li 850 nm, feem ntau siv rau kev sib txuas luv luv multimode fiber optic (xws li cov chaw khaws ntaub ntawv).
Gallium arsenide (GaAs): qhov dav ntawm bandgap ntawm 1.42 eV, qhov cutoff wavelength ntawm kwv yees li 873 nm. Haum rau 850 nm wavelength band, nws tuaj yeem koom ua ke nrog VCSEL lub teeb pom kev zoo ntawm tib cov khoom siv ntawm ib lub nti.
Indium gallium arsenide (InGaAs): Qhov dav ntawm bandgap tuaj yeem hloov kho ntawm 0.36 ~ 1.42 eV, thiab qhov cutoff wavelength npog 873 ~ 3542 nm. Nws yog cov khoom siv ntes tseem ceeb rau 1310 nm thiab 1550 nm fiber sib txuas lus qhov rais, tab sis xav tau InP substrate thiab nyuaj rau kev koom ua ke nrog silicon-based circuits.
Germanium (Ge): nrog rau qhov dav ntawm bandgap kwv yees li 0.66 eV thiab qhov cutoff wavelength kwv yees li 1879 nm. Nws tuaj yeem npog 1550 nm txog 1625 nm (L-band) thiab sib xws nrog silicon substrates, ua rau nws yog ib qho kev daws teeb meem rau kev txuas ntxiv cov lus teb rau cov bands ntev.
Silicon germanium alloy (xws li Si0.5Ge0.5): qhov dav ntawm bandgap txog li 0.96 eV, qhov cutoff wavelength txog li 1292 nm. Los ntawm kev doping germanium hauv silicon, qhov kev teb wavelength tuaj yeem txuas ntxiv mus rau cov bands ntev dua ntawm silicon substrate.
3. Kev koom tes ntawm daim ntawv thov xwm txheej:
850 nm band:Cov duab thaij duab siliconlos yog GaAs photodetectors siv tau.
1310/1550 nm band:Cov duab thaij duab InGaAsfeem ntau yog siv. Cov duab thaij duab germanium lossis silicon germanium alloy ntshiab kuj tseem tuaj yeem npog qhov ntau yam no thiab muaj peev xwm zoo dua hauv kev koom ua ke raws li silicon.

Zuag qhia tag nrho, los ntawm cov ntsiab lus tseem ceeb ntawm kev tshawb fawb band thiab cutoff wavelength, cov yam ntxwv ntawm daim ntawv thov thiab wavelength coverage ntawm cov ntaub ntawv semiconductor sib txawv hauv photodetectors tau raug tshuaj xyuas tsis tu ncua, thiab kev sib raug zoo ntawm kev xaiv cov khoom siv, fiber optic kev sib txuas lus wavelength qhov rai, thiab kev koom ua ke cov nqi tau taw qhia.