Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A Ge specimen is doped with Al. The concentration of acceptor atoms is \(\sim 10^{21}\) atoms \(/ \mathrm{m}^3\). Given that the intrinsic concentration of electron hole pairs is \(10^{19} / \mathrm{m}^3\), the concentration of electrons in the specimen is
PhysicsSemiconductorsAIIMSAIIMS 2008
Options:
  • A \(10^{17} / \mathrm{m}^3\)
  • B \(10^{15} / \mathrm{m}^3\)
  • C \(10^4 / \mathrm{m}^3\)
  • D \(10^2 / \mathrm{m}^3\).
Solution:
1640 Upvotes Verified Answer
The correct answer is: \(10^{17} / \mathrm{m}^3\)
$n_h=10^{21}$ atoms $/ \mathrm{m}^3$
$n_i=10^{19}$ atoms $/ \mathrm{m}^3, n_e=$ ?
$n_e n_h=n_i^2$
$n_e=\frac{n_i^2}{n_h}=\frac{\left(10^{19}\right)^2}{10^{21}}=\frac{10^{38}}{10^{21}}=10^{17}$ atoms $/ \mathrm{m}^3$.

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.