NEETChemistrySolid State
Explain why does conductivity of germanium crystals increase on doping with galium.
Options
- ABecause Galium atom has only three valence electrons. Therefore, fourth valency of nearby germanium atom is no
- BBecause gallium increases the density of germanium crystals.
- CBecause the atomic size of gallium is smaller than that of germanium.
- DBecause gallium changes the colour of germanium crystals.
Correct answer
A. Because Galium atom has only three valence electrons. Therefore, fourth valency of nearby germanium atom is no
Step-by-step solution
Correct Option is : (A) Because Galium atom has only three valence electrons. Therefore, fourth valency of nearby germanium atom is not satisfied. Electron from neighbouring atom comes and fills the gap, thereby creating a hole in its original position. Under the influence of electric field electrons move towards positively charged plates through these holes and conduct electricity.