Key relationship
n−p=ND (n type); np=ni². σ=e(nμn+pμp).
Physics · Class 12
Intrinsic and doped carriers
Donors favor electrons and acceptors favor holes. Minority carriers remain present. At equilibrium the carrier product equals ni² in this nondegenerate model, and ionized dopants preserve overall charge neutrality.
Open the interactive experiment →Intrinsic and doped carriers
கொடையாளர்கள் எலக்ட்ரான்களையும் ஏற்பாளர்கள் துளைகளையும் பெரும்பான்மை கடத்திகளாக்கும். சிறுபான்மை கடத்திகளும் உள்ளன.
Key notes, relationships and model limits
Remember
Donors favor electrons and acceptors favor holes. Minority carriers remain present. At equilibrium the carrier product equals ni² in this nondegenerate model, and ionized dopants preserve overall charge neutrality.
Common trap
An n-type bulk remains electrically neutral; it is not a net negatively charged sample.
Model limits
Fully ionized room-temperature silicon; ni=10¹⁰ cm⁻³; constant mobilities1350 and480 cm²/(V s). No degeneracy or concentration-dependent mobility at heavy doping.
What you will learn
Track majority, minority and intrinsic carriers.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
At ND10¹⁵ cm⁻³, n≈10¹⁵ and p≈10⁵ cm⁻³ under these assumptions.
Why this matters
The model connects intrinsic and doped carriers with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
In an n-type semiconductor, the majority carriers are?
- Holes
- Electrons
- Protons
Read the explanation
Donor doping supplies conduction electrons.
Course connection: Class XII Chapter 14. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.