Consider a n-type semiconductor whose Ev=0, EC=2.0eV and ED-1.98eV. The correct statement among the following… · ABC26PH0183
Subject: Physical Chemistry · Chapter: Solid State Chemistry · Topic: Band Theory · Exam: CSIR NET 2011 · Marks: 2 · Difficulty: Medium
Consider a n-type semiconductor whose $\mathrm{E}_{v}=0, \mathrm{E}_{C}=2.0\mathrm{eV}$ and $\mathrm{E}_{D}-1.98\mathrm{eV}$. The correct statement among the following is
(a)$E_{F}=1\mathrm{eV}$ and is independent of T
(b)$E_{F}=1.99\mathrm{eV}$ and remains independent of T
(c)$E_{F}=1.99 \mathrm{eV}$ and increases towards 2.0 eV with increase of T
(d)$E_{F}=1.99\,\mathrm{eV}$ and decreases with increase of T
Answer
Answer: D ✓ checked by 4AB · confidence medium
Explanation
At low T the Fermi level of an n-type semiconductor lies midway between donor level and conduction band (1.99 eV); as T rises it falls toward the intrinsic midgap value (d).