Band Gap Calculator
Calculate band gap energy and absorption edge wavelength for semiconductors
About Band Gap
The band gap is the energy difference between the valence band and conduction band in a semiconductor. It determines the minimum photon energy required to excite an electron from the valence band to the conduction band.
Key Formulas:
- Eg = hc/λ (photon energy)
- Eg(T) = Eg(0) - αT²/(T+β) (Varshni equation)
- 1240/λ(nm) ≈ Eg(eV) (quick conversion)
Spectral Regions:
- UV: λ < 400 nm → Eg > 3.1 eV
- Visible: 400-700 nm → Eg: 1.8-3.1 eV
- Near IR: 700-1500 nm → Eg: 0.8-1.8 eV
- Mid IR: > 1500 nm → Eg < 0.8 eV