Classify the following semiconductors as n-type or p-type. (a) Si doped with In (b) Ge doped with Sb (c) Gray Sn doped with As

Verified step by step guidance

1. insert step 1> Identify the base element in each semiconductor. Silicon (Si), Germanium (Ge), and Gray Tin (Sn) are all group 14 elements in the periodic table.
2. insert step 2> Determine the group number of the dopant element. Indium (In) is in group 13, Antimony (Sb) is in group 15, and Arsenic (As) is also in group 15.
3. insert step 3> Understand the concept of n-type and p-type semiconductors. N-type semiconductors are created by doping with elements that have more valence electrons than the base element, adding extra electrons. P-type semiconductors are created by doping with elements that have fewer valence electrons, creating 'holes'.
4. insert step 4> Classify each semiconductor: (a) Si doped with In: Indium has fewer valence electrons than Silicon, creating holes, so it is a p-type semiconductor.
5. insert step 5> Classify each semiconductor: (b) Ge doped with Sb: Antimony has more valence electrons than Germanium, adding extra electrons, so it is an n-type semiconductor. (c) Gray Sn doped with As: Arsenic has more valence electrons than Tin, adding extra electrons, so it is an n-type semiconductor.

Key Concepts

Doping in Semiconductors

Doping is the intentional introduction of impurities into a semiconductor to modify its electrical properties. By adding specific elements, the number of charge carriers (electrons or holes) can be increased, enhancing conductivity. N-type doping introduces extra electrons, while p-type doping creates holes by accepting electrons.

N-type Semiconductors

N-type semiconductors are created by doping a pure semiconductor, like silicon (Si) or germanium (Ge), with elements that have more valence electrons than the semiconductor itself, typically from group V of the periodic table. This results in an excess of electrons, which are the majority charge carriers, leading to increased conductivity.

P-type Semiconductors

P-type semiconductors are formed by doping a semiconductor with elements that have fewer valence electrons, usually from group III of the periodic table. This creates 'holes' or vacancies where an electron is missing, making holes the majority charge carriers. The presence of these holes allows for electrical conduction through the movement of positive charge.