1. What is Band Gap Energy?

Band gap energy (E_g) is the energy difference between the top of the valence band and the bottom of the conduction band in materials. It determines the electrical conductivity and optical properties of semiconductors and insulators.

2. How Does the Calculator Work?

The calculator uses the band gap energy equation:

Where:

• \( E_g \) — Band gap energy (J)
• \( h \) — Planck's constant (6.626 × 10⁻³⁴ J·s)
• \( c \) — Speed of light (3 × 10⁸ m/s)
• \( \lambda \) — Wavelength (m)

Explanation: This equation relates the energy of a photon to its wavelength, allowing calculation of the band gap energy from absorption measurements.

3. Importance of Band Gap Calculation

Details: Accurate band gap calculation is crucial for semiconductor material characterization, optoelectronic device design, and understanding material properties for various applications in electronics and photonics.

4. Using the Calculator

Tips: Enter wavelength in meters. The value must be valid (wavelength > 0). The calculator uses standard physical constants for Planck's constant and speed of light.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use for wavelength?
A: The calculator requires wavelength input in meters (m). Convert from other units if necessary (1 nm = 10⁻⁹ m, 1 μm = 10⁻⁶ m).

Q2: Can I use this for any material?
A: This calculation applies to materials where the band gap corresponds to the absorption edge. It works best for direct band gap semiconductors.

Q3: What are typical band gap values?
A: Band gaps range from 0 eV (metals) to several eV (insulators). Common semiconductors: Si (1.1 eV), GaAs (1.43 eV), GaN (3.4 eV).

Q4: How does temperature affect band gap?
A: Band gap generally decreases with increasing temperature due to lattice expansion and electron-phonon interactions.

Q5: Can I convert the result to electronvolts (eV)?
A: Yes, divide the result in joules by 1.602 × 10⁻¹⁹ to convert to electronvolts (1 eV = 1.602 × 10⁻¹⁹ J).