Pure Si at 500 K has equal number of electron (nₑ) and hole (nₕ) concentrations

⇦

⇨

Pure Si at 500 K has equal number of electron (nₑ) and hole (nₕ) concentrations of 1.5 x 10¹⁶ m⁻³. Doping by indium increases nₕ to 4.5 x 10²² m⁻³. The doped semiconductor is of

Options

(a) n-type with electron concentration nₑ = 5 x 10²² m⁻³
(b) p-type with electron concentration nₑ = 2.5 x 10¹⁰ m⁻³
(c) n-type with electron concentration nₑ = 2.5 x 10²³ m⁻³
(d) p-type with electron concentration nₑ = 5 x 10⁹ m⁻³

Correct Answer:

p-type with electron concentration nₑ = 5 x 10⁹ m⁻³

Explanation:

nᵢ² = nₑ nₕ
(1.5 x 10¹⁶)² = nₑ (4.5 x 10²²)
⇒ nₑ = 0.5 x 10¹⁰ or nₑ = 5 x 10⁹
Given nₕ = 4.5 x 10²² ⇒ nₕ >> nₑ
semiconductor is p-type and
nₑ = 5 x 10⁹ m⁻³.

Related Questions:

1. In common base circuit of a transistor, current amplification factor is 0.95.
2. A body of mass 3 kg acted upon by a constant force is displaced by S meter
3. Excitation energy of a hydrogen like ion, in its first excitation state, is 40.8 eV.
4. A particle of mass m is driven by a machine that delivers a constant power k watts
5. A charged particle experiences magnetic force in the presence of magnetic field.

Topics: Electronic Devices (124)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends