Led Emission Principle

Question

LED emits light when?

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1. **LED Core**: A Light Emitting Diode is a heavily doped PN junction made from compound semiconductors like GaAsP.
2. **Mechanism**: Under **forward bias**, electrons from the N-side and holes from the P-side are injected into the junction region.
3. **Recombination**: In the junction, free electrons 'fall' into vacancies (holes). During this **recombination** process, energy is released.
4. **Photon Emission**: In these specific materials (direct band gap), the released energy appears in the form of **photons** of light.
5. **Calculation**: The wavelength of light depends on the energy gap ($E_g = hf = hc/\lambda$).

Led Emission Principle

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