1. What is Quantum Efficiency?

Definition: Quantum efficiency (QE) measures how effectively a device converts incident photons into emitted photons or electrons.

Purpose: It's a crucial parameter for evaluating the performance of photodetectors, solar cells, and light-emitting devices.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( QE \) — Quantum efficiency (percentage)
• \( N_p \) — Number of photons emitted or electrons generated
• \( N_i \) — Number of incident photons

Explanation: The ratio of emitted photons to incident photons, multiplied by 100 to get a percentage.

3. Importance of Quantum Efficiency

Details: Higher QE means better performance. Solar cells with high QE convert more sunlight to electricity, while detectors with high QE are more sensitive.

4. Using the Calculator

Tips: Enter the number of photons emitted and the number of incident photons. Incident photons must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a good quantum efficiency value?
A: Values range from 0-100%. Silicon photodetectors typically achieve 60-90% QE in their sensitive wavelength range.

Q2: Can QE exceed 100%?
A: In some special cases (like avalanche photodiodes), effective QE can exceed 100% due to internal gain mechanisms.

Q3: How is QE different from power efficiency?
A: QE counts photons, while power efficiency considers energy. They differ when photon energies vary.

Q4: Does QE depend on wavelength?
A: Yes, most devices have wavelength-dependent QE, usually specified in datasheets.

Q5: How do I measure N_p and N_i?
A: Use calibrated photodetectors and light sources, or refer to device specifications.