Compound semiconductors

Which is a characteristic of multi-junction solar cells, which stack several compound semiconductor layers with different band gaps?

  1. AThey make efficient use of a wide range of sunlight wavelengths and achieve high conversion efficiency
  2. BThey have the lowest material cost
  3. CThey can generate electricity even where there is no light
Show answer and explanation

Answer: A. They make efficient use of a wide range of sunlight wavelengths and achieve high conversion efficiency

With a single material, light below the band gap cannot be absorbed, and excess energy from higher-energy light is lost as heat. In a multi-junction solar cell, layers with different band gaps each absorb the wavelengths they handle best, achieving high conversion efficiency. Because they are expensive, they are used in satellites and similar applications.

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More Compound semiconductors questions

  1. Which impurity is typically used to make p-type layers in GaN?
  2. What is the typical crystal structure of GaN?
  3. Which is an example of an application of HBTs (heterojunction bipolar transistors) made from InP or GaAs?
  4. When silicon is added to GaAs to make it n-type, which site does the silicon mainly occupy?
  5. What is the advantage of using semi-insulating GaAs substrates for GaAs RF ICs?