Physical/Inorganic · Band Theory
Band Theory & Semiconductors
Exam-focused revision notes on Band Theory & Semiconductors for CSIR-NET Chemical Sciences, GATE Chemistry and IIT-JAM — the core concepts, the formulas worth memorising, the traps that cost marks, and a quick-recall table.
From orbitals to bands
In a single atom, electrons sit in discrete atomic orbitals. Bring N atoms together in a solid and each orbital overlaps with those on neighbouring atoms, forming N closely spaced molecular orbitals. With N huge (~1023), the levels merge into an effectively continuous band.
What this note covers
- 1From orbitals to bands
- 2Conductor, insulator, semiconductor
- 3Intrinsic vs extrinsic semiconductors
- 4Doping — n-type and p-type
- 5Fermi level
- 6Temperature dependence (very common in exams)
- 7Common traps students miss
- 8Summary table
Read the full note
The remaining 7 sections — including the worked examples, the common-traps list and the quick-recall table — are part of ChemVidya Full Access, along with 6,000+ practice questions.
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