Band visualizer

Semiconductor Band Gap Explorer

Interactive physics visualization & Varshni dynamics

Configure Band Structure

Adjust the parameters below to observe how the band gap dictates electrical conductivity. A small band gap allows thermal energy to easily excite valence electrons into the conduction band.

Preset Material Types

Band Gap ($E_g$) 1.12 eV

0 eV (Conductor) >4 eV (Insulator)

Thermal Energy Factor ($kT$) Medium (300 K)

0 K (Cryogenic) Very Hot

Quick Physics Check:

In semiconductors, the valence band (filled) is separated from the conduction band (empty) by a relatively small energy gap $E_g$.

As temperature increases, thermal excitation increases the probability of an electron jumping the gap, creating a mobile electron-hole pair.

Interactive Band Occupancy Diagram

Semiconductor

Free Electron Empty Hole

Thermal Dynamics

In semiconductors, the band gap is not fixed. It contracts with rising temperature due to lattice expansion and increased electron-phonon interactions.

Varshni Empirical Relation:

$$E_g(T) = E_g(0) - \frac{\alpha T^2}{T + \beta}$$

Select Material

Bandgap at 0K ($E_g(0)$): 1.17 eV

Coefficient ($\alpha$): 4.73 × 10⁻⁴ eV/K

Debye Temperature ($\beta$): 636 K

Set Temperature (K) 300 K (26.85 °C)

Varshni Curve Plot ($E_g$ vs. Temperature)

At 300K: 1.125 eV

Observation: As the temperature approaches absolute zero ($0\text{ K}$), the band gap plateaus. For high temperatures, it decreases almost linearly. This property is crucial for design parameters in thermoelectric power, semiconductor optical devices, and high-temperature power electronics.

Momentum Space Dynamics

To understand modern optoelectronics (like LEDs, lasers, and solar cells), we must examine energy ($E$) as a function of the electron's momentum wavevector ($k$).

Crystal Structure Type

Physics Principle:

Light emission or absorption is fundamentally a transition. Photons carry negligible momentum ($k \approx 0$). Thus, in a Direct Gap semiconductor, an electron can transition vertically by emitting/absorbing a photon alone.

The E-k Diagram Energy Bands

© 2026 Semiconductor Band Gap Explorer. Formulated with physical Constants & Empirical Varshni parameters.

Created with Gemini for testing.