Mtima wa Ma Laser a Semiconductor: Kumvetsetsa PN Junction

Chifukwa cha kupita patsogolo kwa ukadaulo wa optoelectronic mwachangu, ma laser a semiconductor apeza ntchito zambiri m'magawo monga kulumikizana, zida zamankhwala, kugwiritsa ntchito ma laser, kukonza mafakitale, ndi zamagetsi. Pakati pa ukadaulo uwu pali PN junction, yomwe imagwira ntchito yofunika kwambiri—osati kokha ngati gwero la kuwala komanso ngati maziko a ntchito ya chipangizocho. Nkhaniyi ikupereka chithunzithunzi chomveka bwino komanso chachidule cha kapangidwe, mfundo, ndi ntchito zazikulu za PN junction mu ma laser a semiconductor.

1. Kodi PN Junction ndi chiyani?

PN junction ndi njira yolumikizirana yomwe imapangidwa pakati pa semiconductor ya P-type ndi semiconductor ya N-type:

Semiconductor ya mtundu wa P imadzazidwa ndi zinthu zodetsa monga boron (B), zomwe zimapangitsa mabowo kukhala onyamula mphamvu zambiri.

Semiconductor ya mtundu wa N imadzazidwa ndi zinthu zodetsa monga phosphorous (P), zomwe zimapangitsa ma elekitironi kukhala onyamula ambiri.

Pamene zinthu za mtundu wa P ndi mtundu wa N zilumikizidwa, ma elekitironi ochokera ku dera la N amafalikira kupita ku dera la P, ndipo mabowo ochokera ku dera la P amafalikira kupita ku dera la N. Kufalikira kumeneku kumapanga dera lochepa kumene ma elekitironi ndi mabowo amalumikizananso, ndikusiya ma ayoni omwe amayendetsedwa omwe amapanga gawo lamagetsi lamkati, lodziwika kuti chotchinga chomangidwa mkati.

2. Udindo wa PN Junction mu Lasers

(1) Jakisoni wa Chonyamulira

Pamene laser ikugwira ntchito, malo olumikizirana a PN amakhala kutsogolo: dera la P limalumikizidwa ndi voltage yabwino, ndipo dera la N limalumikizidwa ndi voltage yoyipa. Izi zimaletsa mphamvu yamagetsi yamkati, zomwe zimapangitsa kuti ma elekitironi ndi mabowo azilowetsedwa m'dera logwira ntchito pamalo olumikizirana, komwe angagwirizanenso.

(2) Kutulutsa Mpweya Wowala: Chiyambi cha Kutulutsa Mpweya Wolimbikitsidwa

Mu gawo logwira ntchito, ma elekitironi ndi mabowo omwe amalowetsedwa amalumikizananso ndikutulutsa ma photoni. Poyamba, njirayi imachitika mwadzidzidzi, koma pamene kuchuluka kwa ma photoni kumawonjezeka, ma photoni amatha kuyambitsa kubwerezabwereza kwa ma elekitironi ndi mabowo, ndikutulutsa ma photoni ena okhala ndi gawo lomwelo, njira, ndi mphamvu - izi ndi kutulutsa kolimbikitsidwa.

Njira imeneyi imapanga maziko a laser (Light Amplification by Stimulated Emission of Radiation).

(3) Mabowo Okhala ndi Gain ndi Resonant Ochokera ku Laser Output

Kuti awonjezere kutulutsa kwamphamvu, ma laser a semiconductor amaphatikizapo ma resonant cavities mbali zonse ziwiri za PN junction. Mwachitsanzo, mu ma laser otulutsa m'mphepete, izi zitha kuchitika pogwiritsa ntchito Distributed Bragg Reflectors (DBRs) kapena magalasi ophimba kuti awonetse kuwala kumbuyo ndi mtsogolo. Kukhazikitsa kumeneku kumalola kuti mafunde enaake a kuwala akule, zomwe pamapeto pake zimapangitsa kuti laser ituluke bwino komanso molunjika.

3. Kapangidwe ka PN Junction ndi Kukonza Kapangidwe

Kutengera mtundu wa laser ya semiconductor, kapangidwe ka PN kangasiyane:

Heterojunction imodzi (SH):
Chigawo cha P, chigawo cha N, ndi chigawo chogwira ntchito zimapangidwa ndi chinthu chomwecho. Chigawo chophatikizana ndi chachikulu komanso chosavuta kugwiritsa ntchito.

Kulumikizana kwa Hetero (DH) kawiri:
Gawo lochepa la bandgap limayikidwa pakati pa zigawo za P- ndi N. Izi zimaletsa zonyamulira ndi ma photon, zomwe zimapangitsa kuti magwiridwe antchito azigwira ntchito bwino kwambiri.

Kapangidwe ka Chitsime cha Quantum:
Imagwiritsa ntchito gawo logwira ntchito lochepa kwambiri kuti ipange zotsatira za quantum confinement, kukonza makhalidwe a threshold ndi modulation speed.

Mapangidwe onsewa adapangidwa kuti awonjezere mphamvu ya jakisoni wonyamula, kubwezeretsanso, komanso kutulutsa kuwala m'dera la PN junction.

4. Mapeto

Malo olumikizirana a PN ndi "mtima" wa laser ya semiconductor. Kutha kwake kulowetsa zonyamulira pansi pa bia ya kutsogolo ndiye chifukwa chachikulu chopangira laser. Kuyambira kapangidwe ka kapangidwe kake ndi kusankha zinthu mpaka kulamulira photon, magwiridwe antchito a chipangizo chonse cha laser amayang'ana kwambiri kukonza malo olumikizirana a PN.

Pamene ukadaulo wa optoelectronic ukupitilira patsogolo, kumvetsetsa bwino kwa fizikisi ya PN junction sikuti kumangowonjezera magwiridwe antchito a laser komanso kumayika maziko olimba a chitukuko cha m'badwo wotsatira wa ma laser a semiconductor amphamvu kwambiri, othamanga kwambiri, komanso otsika mtengo.