Question

Draw the energy band diagram when intrinsic semiconductor (Ge) is doped
with impurity atoms of Antimony (Sb). Name the extrinsic semiconductor so
obtained and majority charge carriers in it.​

Answer 1

• Semiconductor, as the name suggests is a kind of material whose shows properties of both conductors and insulators. A semiconductor material requires a certain level of voltage or heat to release its carriers for conduction. These semiconductors are classified as ‘intrinsic’ and ‘extrinsic’ based on the number of carriers. The intrinsic carrier is the purest form of semiconductor and an equal number of electrons (negative charge carriers) and holes (positive charge carriers). The semiconductor materials most profoundly used are Silicon (Si), Germanium (Ge), and Gallium Arsenide (GaAs). Let us study the characteristics and behavior of these types of semiconductors.

• What is an Intrinsic Semiconductor?

• The Intrinsic semiconductor can be defined as chemically pure material without any doping or impurity added to it. The most commonly known intrinsic or pure semiconductors available are Silicon (Si) and Germanium (Ge). The behavior of the semiconductor on applying a certain voltage is dependent on its atomic structure. The outermost shell of both Silicon and Germanium have four electrons each. To stabilize each other nearby atoms form covalent bonds based on the sharing of valence electrons. This bonding in the crystal lattice structure of Silicon is illustrated in figure 1. Here it can be seen that the valence electrons of two Si atom pair together to form a Covalent Bond.