Me kuke so kuwa Schottky?

Me da shi Schottky Effect?

Takardunin Schottky Effect

Schottky effect ita ce kalmomin da yaɗuwa mai gaba-gaba a zabe zuwa wata tsakiyar a kan gabashin abincin yadda aka baka fadin kai. Wannan na taimaka wajen kawo elektronon daga abincin da aka koyarwa kuma na iya haɗa suka ta hanyar jirgin thermionic, fadin ionization na rubuce-rubuce, da kuma sautin photoelectric. An sanya wannan bayanan Walter H. Schottky, wanda yake da muhimmanci a wurare masana'antu da ke amfani da elektronon kamar electron guns.

Thermionic Emission

Don in fahimtar Schottky effect, muna buƙatar in nemo thermionic emission da work function.

Thermionic emission ita ce fitowa (karɓe) da za'a samun charge carriers (ions ko electrons) daga gabashin abinci saboda energy mai yawa da aka baka. A cikin abinci mai sauƙi, ana fiye da elektronon miliyan da biyu a kan kowace atom da za su iya zo daga atom zuwa atom basu a cikin band theory. Wanene daga cikinsu zai iya fito daga gabas idan an yi magance energy da za su iya doke potential barrier wanda ya kula su a kan abinci.

Work function ita ce energy mai ɗaya da ya dace don elektron ya fito daga gabashin abinci saboda energy mai yawa. Yana canzawa da abinci, crystal structure, yanayi na gabas, da kuma tsari. Work function mai kadan yana taimaka wajen karɓar elektronon da ya fito.

Ingantaccen current density J da temperature T ta abinci mai koyarwa ita ce an bayyana a cikin Richardson’s law, wanda yake da damar Arrhenius equation:

Amsa, W ita ce work function ta metal, k ita ce Boltzmann constant, AG ita ce product of a universal constant A0 multiplied by a material-specific correction factor λR which is typically of order 0.5.

Rolin Fadin Kai

Nun, za a iya bayyana yadda fadin kai ya taimaka wajen haɗa thermionic emission kuma yadda ya haɗa Schottky effect.

Idan an baka fadin kai a abinci mai koyarwa, za a iya kawo lowla potential barrier, wanda yake taimaka masu elektronon da za su iya fito. Wannan na kawo lowla work function da amount ΔW, wanda yake taimaka karɓar thermionic. Barrier lowering ΔW ita ce an rarrabe ne a cikin:

Richardson equation da aka ɗaukan yadda ake kawo lowla barrier ita ce:

Richardson equation da aka ɗaukan yadda ake kawo lowla barrier ita ce:

This equation describes the Schottky effect or field-enhanced thermionic emission, which occurs when a moderate electric field (lower than about 108 V/m) is applied to a heated material.

Field Emission

Idan an baka fadin kai mai yawan (da yawan da 108 V/m) a abinci mai koyarwa, zai faru ɗaya daga elektronon da za su fito wanda ake kira field emission ko Fowler-Nordheim tunneling.

A nan, fadin kai yana da yawa sosai kuma yana kawo lowla potential barrier da ya kula elektronon su ka tunza saboda ba su da magance thermal energy ba. Wannan ɗaya daga fitowa ko tunza ba su da yawan temperature, amma ana neman da yawan fadin kai.

Muhimman abubuwan field-enhanced thermionic da field emission zai iya model da Murphy-Good equation for thermo-field (T-F) emission. A yawan fadin kai, field emission zai zama yanayin karɓar elektronon, kuma emitter zai yi aiki a cikin “cold field electron emission (CFE)” regime.

Applications

Schottky effect ita ce amfani da shi a wurare masana'antu kamar electron microscopes, vacuum tubes, gas discharge lamps, solar cells, da kuma nanotechnology.

Summary

Schottky effect ita ce bayanai a physics wanda yake kawo lowla energy da ya dace don elektronon su fito daga gabashin abinci a kan gabashin abincin yadda aka baka fadin kai. Wannan na taimaka wajen karɓar fitowa daga gabashin abinci mai koyarwa kuma na iya haɗa suka ta hanyar jirgin thermionic, fadin ionization na rubuce-rubuce, da kuma sautin photoelectric.

Schottky effect ita ce idan fadin kai mai yawan ya kawo lowla potential barrier wanda ya kula elektronon su ka fito daga gabas, wanda yake kawo lowla work function da karɓar thermionic. Ingantaccen thermionic current density da temperature, work function, da yawan fadin kai zai iya bayyana a cikin modified Richardson equation.