1. What is Quantum Efficiency?

Definition: Quantum efficiency (QE) measures the effectiveness of a device in converting incident photons into emitted photons or electrons.

Purpose: It's crucial for evaluating the performance of photodetectors, solar cells, LEDs, and other optoelectronic 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 output photons to input photons, multiplied by 100 to get a percentage.

3. Importance of Quantum Efficiency

Details: Higher QE means better device 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 emitted photons and incident photons. Both values must be ≥ 0, and 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 photodiodes typically achieve 60-90%, while some specialized detectors can approach 100%.

Q2: How is this different from external quantum efficiency?
A: This calculator measures internal QE. External QE accounts for reflection losses and other factors.

Q3: Can QE exceed 100%?
A: Normally no, but in avalanche photodiodes or with multiple exciton generation, effective QE can appear >100%.

Q4: How do I measure photons emitted/incident?
A: Use calibrated photodetectors and light sources, or refer to device specifications.

Q5: Does wavelength affect QE?
A: Yes, QE is typically wavelength-dependent. This calculator assumes monochromatic light.