Determine the wavelength of the light emitted from LED, which is made up of GaAsP semiconductor, whose forbidden energy gap is 1.875 eV. Mention the colour of the light emitted (Given $h = 6.6 \times 10^{-34}$ Js).

Determine the wavelength of the light emitted from LED, which is made up of GaAsP semiconductor, whose forbidd

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h = 6.6 \times 10^{-34}

Tamil Nadu DgeTamil Nadu HSC (DGE) Board 2024Subjective· 3mImportance★★★★★

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Converting the GaAsP LED's band gap of $1.875$ eV to an emitted-photon wavelength via $\lambda=hc/E_g$ gives $\lambda\approx660$ nm, which lies in the red region of the visible spectrum.

Working

When a forward-biased LED conducts, electrons and holes recombine at the junction, releasing energy approximately equal to the semiconductor's band gap $E_g$ as a photon:

$E_g = h\nu = \dfrac{hc}{\lambda} \ \Rightarrow\ \lambda = \dfrac{hc}{E_g}$

Given: $E_g = 1.875$ eV $= 1.875\times1.6\times10^{-19}\ \text{J} = 3.0\times10^{-19}$ J; $h=6.6\times10^{-34}$ Js; $c=3\times10^8$ ms $^{-1}$ .

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Q.Determine the wavelength of the light emitted from LED, which is made up of GaAsP semiconductor, whose forbidden energy gap is 1.875 eV. Mention the colour of the light emitted (Given $h = 6.6 \times 10^{-34}$ Js).

Concept understanding — Light Emitting Diode (LED)

Q.Determine the wavelength of the light emitted from LED, which is made up of GaAsP semiconductor, whose forbidden energy gap is 1.875 eV. Mention the colour of the light emitted (Given h=6.6×10−34h = 6.6 \times 10^{-34}h=6.6×10−34 Js).

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Q.Determine the wavelength of the light emitted from LED, which is made up of GaAsP semiconductor, whose forbidden energy gap is 1.875 eV. Mention the colour of the light emitted (Given $h = 6.6 \times 10^{-34}$ Js).

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