PN junctions and diodes

Which value is closest to the theoretical maximum efficiency of a single-junction solar cell (the Shockley-Queisser limit)?

  1. AAbout 100%
  2. BAbout 80%
  3. CAbout 33%
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Answer: C. About 33%

A single PN junction solar cell cannot absorb light with energy below the band gap, and the excess energy of higher-energy light is lost as heat. As a result, even with the optimal band gap, the theoretical efficiency limit is about 33%. Multi-junction solar cells and other approaches are being studied to exceed it.

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More PN junctions and diodes questions

  1. How does the avalanche breakdown voltage generally change as temperature rises?
  2. What is the phenomenon in which forward current through a PIN diode injects many carriers into the i-layer and greatly reduces its resistance?
  3. What can be evaluated by measuring the capacitance of a reverse-biased PN junction while varying the voltage (C-V measurement)?
  4. Of the two terminals of a PN junction diode, what is the terminal on the p-type side called?
  5. What is the property of a diode that lets current flow easily in one direction but hardly at all in the other called?