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Additional factoid: these are known as III-V semiconductors after their columns in the periodic table / number of valence electrons. They all have different ban

by sevensor 10mo ago

Additional factoid: these are known as III-V semiconductors after their columns in the periodic table / number of valence electrons. They all have different bandgaps and lattice constants, and interesting things happen when you modulate composition. Also, you might actually want to introduce a lattice constant mismatch because the strained lattice has useful properties.

AnimalMuppet 10mo ago
Additional additional factoid: "Gallium Arsenide" would be a great name for a speed metal band.
adrian_b 10mo ago
Close, but no match. Cadmium zinc telluride is a II-VI semiconductor, not a III-V semiconductor, because Cd & Zn belong to the 2nd group, while Te belongs to the 6th group. (I find the habit of some modern authors of calling the group 2b as group 12 and the group 6a as group 16 extremely stupid, even if with the traditional approach it is debatable which should be group 2a and which should be group 2b, because for many properties Zn, Cd & Hg are more similar to Mg than Mg is similar to Ca, Sr & Ba. However this defect of the classic numbering is not solved, but it is made worse in the modern numbering.) Both the III-V & the II-VI semiconductors, and also the few existing I-VII (made of Cu or Ag with halogens) and the few IV-IV semiconductors (e.g. silicon carbide) semiconductors, are compounds of chemical elements whose number of external electrons averages to 4, i.e. the same as in diamond, silicon or germanium, so they can form crystal structures of the same kind. There are many other kinds of semiconductors, but those which have the cubic or hexagonal structures of diamond/lonsdaleite (more symmetric) or zinc sulfide (less symmetric) are much better understood than the other semiconductors and they are much more frequently used.
- sevensor 10mo ago
  Good point, I was responding to a the parent talking about GaAs, but CdZnTe is certainly II-VI.

AnimalMuppet 10mo ago

Additional additional factoid: "Gallium Arsenide" would be a great name for a speed metal band.

adrian_b 10mo ago

Close, but no match. Cadmium zinc telluride is a II-VI semiconductor, not a III-V semiconductor, because Cd & Zn belong to the 2nd group, while Te belongs to the 6th group. (I find the habit of some modern authors of calling the group 2b as group 12 and the group 6a as group 16 extremely stupid, even if with the traditional approach it is debatable which should be group 2a and which should be group 2b, because for many properties Zn, Cd & Hg are more similar to Mg than Mg is similar to Ca, Sr & Ba. However this defect of the classic numbering is not solved, but it is made worse in the modern numbering.) Both the III-V & the II-VI semiconductors, and also the few existing I-VII (made of Cu or Ag with halogens) and the few IV-IV semiconductors (e.g. silicon carbide) semiconductors, are compounds of chemical elements whose number of external electrons averages to 4, i.e. the same as in diamond, silicon or germanium, so they can form crystal structures of the same kind. There are many other kinds of semiconductors, but those which have the cubic or hexagonal structures of diamond/lonsdaleite (more symmetric) or zinc sulfide (less symmetric) are much better understood than the other semiconductors and they are much more frequently used.

sevensor 10mo ago
Good point, I was responding to a the parent talking about GaAs, but CdZnTe is certainly II-VI.