Compound semiconductors

Which is a characteristic of a VCSEL (vertical-cavity surface-emitting laser)?

  1. AIt emits light parallel to the substrate and cannot be tested without cleaving
  2. BLike an LED, it emits only spontaneous emission
  3. CIt emits light perpendicular to the substrate, can easily be tested on the wafer, and is easy to arrange in 2D arrays
Show answer and explanation

Answer: C. It emits light perpendicular to the substrate, can easily be tested on the wafer, and is easy to arrange in 2D arrays

A VCSEL has a resonator sandwiched between multilayer mirrors above and below and emits laser light perpendicular to the wafer surface. It can be tested on the wafer and many devices can be arranged in 2D arrays, so it is used as the light source for smartphone face authentication and in data-center optical communication.

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More Compound semiconductors questions

  1. Why is care needed when handling GaAs wafer processing debris and waste?
  2. Why is GaN well suited to high-frequency, high-power transistors?
  3. What is one main reason SiC is used as the substrate for GaN HEMTs?
  4. Which material is mainly used in the light-emitting layer of deep-ultraviolet LEDs, such as those for sterilization?
  5. Which is a characteristic of multi-junction solar cells, which stack several compound semiconductor layers with different band gaps?