What is the value of energy gap in semiconductor?

The energy gap (also called band gap) in a semiconductor is the energy difference between the valence band and the conduction band, typically around 0.5 – 3.0 electronvolts.

More detail: In a solid material, electrons occupy energy levels grouped into bands. The valence band is full of electrons. The conduction band is where electrons are free to move and conduct electricity. The “energy gap” or “band gap” (symbol E₉) is the minimum energy an electron must gain to jump from the valence band to the conduction band and become a free carrier. :contentReference[oaicite:0]{index=0}

Typical values & examples

Why the value matters

• Electrical conductivity: If the band gap is small, electrons can more easily jump and thus the material is more conductive. If the gap is large, fewer electrons make the jump, making it more insulating. :contentReference[oaicite:4]{index=4}
• Optical absorption & emission: The band gap determines what wavelengths of light the material absorbs or emits. Eg an LED material band gap determines its colour. :contentReference[oaicite:5]{index=5}
• Thermal behaviour: With increasing temperature the band gap may decrease, influencing performance of semiconductor devices. :contentReference[oaicite:6]{index=6}
• Choosing material for application: For high-voltage, high-temperature devices you might pick a “wide-gap” semiconductor. For low-power, light-emitting devices maybe a smaller gap. :contentReference[oaicite:7]{index=7}