Yadda Ya Kammala LED?

LED Yadda Ake Tafiya?

Makaranta LED

LED ko Light Emitting Diode, ana kiranta da ita ce wasan tafiya wanda yake tafiya idan an kiran shi da takara kan wasu na iya ba da aiki da sunan electroluminescence.

Yadda LED Ya Tafiya

Daga cikin dioda mai zurfi, LED ya tafiya idan an kiran shi da takara. A wannan halin, n-type semiconductor ya fi sanya da p-type don fadada p-n junction. Idan an kiran shi da takara, manufar ta tsakiyar zama da aka sauti da electrons da holes suka haɗa a cikin depletion layer (ko active layer), tafiyar ko photons suka fitowa duka hawan. Wani abubuwa masu tafiya na electron-hole pair combining a cikin forward biasing.

Tafiya photons a cikin LED ana bayyana da energy band theory of solids, wanda ke nuna cewa tafiya tafiya depends on the material’s band gap being direct or indirect. Wasu materials da suka samun band gap direct su ne wadanda suka fitowa photons. A cikin material da suka samun bandgap direct, kofin energy level of conduction band yake zaune a cikin energy level of valence band a Energy vs Momentum (wave vector ‘k’) diagram.

Idan electrons da hole suka haɗa, E = hν corresponding to the energy gap △ (eV) ya fitowa a cikin tafiya ko photons inda h shine Planck’s constant da ν shine frequency of light.

Direct Band Gap

Materials da suka samun indirect band gap ba su tafiya, saboda kofin conduction band ba su zama da kofin valence band, wanda ke taka muhimmanci a yi heat. Misaaluna Si, Ge etc.

Indirect Band Gap

Misaalai da suka samun direct band gap shine Gallium Arsenide(GaAs), wata compound semiconductor wanda ake amfani da shi a LEDs. Dopant atoms suka zama da suka bari da GaAs don bayar da karfin rangon. Wasu materials da ake amfani da su a LEDs:

• Aluminium Gallium Arsenide(AlGaAs) – infrared.

• Gallium Arsenic Phosphide(GaAsP) – red, orange, yellow.

• Aluminium Gallium Phosphide(AlGaP) – green.

• Indium gallium nitride (InGaN) – blue, blue-green, near UV.

• Zinc Selenide(ZnSe) – blue.

Karakara LED

LED ya fara da hakan haka don haka muna tafiya ya ba su fitowa a cikin material. Saboda haka an tabbatar da electron-hole recombination ya faru a tsakanin.

Wannan abubuwa ya nuna biyu na farko na structuring LED p-n junction. P-type layer ya zama mai kadan da ake gina a cikin n-type substrate. Metal electrodes da ake tsari a duk biyu na p-n junction su ne nodes for external electrical connection. LED p-n junction ya kashe a cikin dome-shaped transparent case don tafiya ya fitowa duka hawan da internal reflection da take place.

Leg da ya fiye da LED ya zama positive electrode ko anode.

LEDs da legs da su da 2 suke da su, misali 3, 4 da 6 pin configurations don samun rangon a cikin LED package. Surface mounted LED displays suke da su don amfani da PCBs.

LEDs typically require a current of a few tens of milliamps and need high resistance in series due to their higher forward voltage drop of 1.5 to 3.5 volts, compared to ordinary diodes.

White Light LEDs ko White LED Lamps

LED lamps, bulbs, street lighting suke da su a lokacin da ya zo saboda efficiency da LED suke da su a light output per unit input power(in milliWatts), compared to incandescent bulbs. Don general purpose lightings, white light ya zama da ma'ana. Don samun white light with the help of LEDs, biyu na methods suke amfani da su:

Mixing of three primary colors RGB to produce white light. This method has high quantum efficiency.

The other method is coating an LED of one color with phosphor of a different color in order to produce white light. This method is commercially popular to manufacture LED bulbs and lightings.

Applications of LEDs

Electronic displays such as OLEDs, micro-LEDs, quantum dots etc.

• As an LED indicator.

• In remote controls.

• Lightings.

• Opto-isolators.