Class 12 Physics simulations · Semiconductor Electronics

LED colour and band gap

Change the semiconductor band gap and see the colour of light the LED emits.

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What to notice

Wider band gaps release more energetic photons — towards blue and violet.

Key relation

λ = hc / E_g ≈ 1240 nm·eV / E_g

Try this

Find the band gap that gives red light (≈ 630 nm).

What you can change

• Band gap E_g: 1.4 to 3.3 eV
• Forward current: 0 to 30 mA

More in Semiconductor Electronics

• Electrons and holes in doped silicon
• P–N junction diode
• Diode I–V characteristic
• Logic gates
• Half-wave rectifier
• Rectifier with a smoothing capacitor
• Solar cell: I–V curve and maximum power
• Transistor as a switch
• Zener voltage regulator

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