Which element, or combination of elements, could produce a semiconductor with the following band structure? (CB = conduction band, VB = valence band)
A) Pure Si
B) Si and C
C) Si and In
D) Si and Sb
E) Si and F

Question

Which element, or combination of elements, could produce a semiconductor with the following band structure? (CB = conduction band, VB = valence band) 
A) Pure Si 
B) Si and C 
C) Si and In 
D) Si and Sb 
E) Si and F

Quizplus · Accepted Answer

The given band structure shows a small band gap, which indicates a semiconductor material. The presence of a shallow donor level (indicated by TD) suggests that the material is doped with an impurity that has one more valence electron than the semiconductor. In this case, the most likely impurity is antimony (Sb), which has five valence electrons compared to silicon's four. Therefore, Si doped with Sb can produce a band structure as shown in the given figure.

Which Element, or Combination of Elements, Could Produce a Semiconductor