What happens to the hole concentration as the temperature increases or decreases?

As the temperature is increased, more electrons become trapped in acceptor sites, until all the acceptors are ionized, causing the hole concentration to increase.

What happens when impurities are added to semiconductors?

Impurities are added into a semiconductor to actually increase the electric conductivity. The process of adding an impurity into the semiconductor to increase its ability to conduct electricity is known as doping and the impure semiconductor is known as a doped semiconductor.

When the temperature of a doped semiconductor increases its resistivity?

If the temperature of a semiconductor is increased then its resistance decreases.

How does increasing temperature affect the concentration of both electrons and holes in an intrinsic semiconductor group of answer choices?

The main effect of temperature on an intrinsic semiconductor is that resistivity decreases with an increase in temperature. This is because heating increases the concentration of electrons and holes because electron/hole pairs are thermally generated at a higher rate.

What is impurity concentration?

electrical properties of semiconductors There is a critical concentration of impurities Nc, which depends on the type of impurity. For impurity concentrations less than the critical amount Nc, the conduction electrons become bound in traps at extremely low temperatures, and the semiconductor becomes an insulator.

How does the suitable impurity increase the conductivity of a semiconductor?

The conductivity of semiconductors is increased by adding an appropriate amount of suitable impurity or doping. Doping can be done with an impurity which is electron rich or electron deficient as compared to the intrinsic semiconductor silicon or germanium. Such impurities introduce electronic defects in them.

Which of the following are acceptor atoms?

Elements like phosphorus, antimony, bismuth, arsenic etc. are donor impurities. While boron, gallium, aluminium etc. are acceptor impurity atoms.

What is a hole in a semiconductor material?

Holes and electrons are the two types of charge carriers responsible for current in semiconductor materials. A hole is the absence of an electron in a particular place in an atom. In N-type semiconductor material, electrons are the majority carriers and holes are the minority carriers.

What is a hole in a semiconductor?

A hole can be seen as the “opposite” of an electron. Unlike an electron which has a negative charge, holes have a positive charge that is equal in magnitude but opposite in polarity to the charge an electron has. These semiconductors, where holes are the most prominent charge carrier, are known as p-type.

When the temperature of semiconductor is increased then its resistance decreases?

In semiconductor the energy gap between conduction band and valence band is small (≈1eV). Due to temperature rise, electron in the valence band gained thermal energy and may jump across the small energy gap, goes in to the conduction band. Thus conductivity increases and hence resistance decreases.

What is doping in semiconductor materials?

These concentrations can be changed by many orders of magnitude by doping, which means adding to a semiconductor impurity atoms that can “donate” electrons to the conduction band (such impurities are called donors) or “accept” electrons from the valence band creating holes (such impurities are called acceptors).

How many holes does each acceptor create in a p-type semiconductor?

In a similar way, at room temperature or elevated temperatures, each acceptor creates one hole in the valence band, and the hole concentration, p, in the valence band of a p -type semiconductor is approximately equal to the acceptor concentration, Na.

What is an acceptor atom in a semiconductor?

An acceptor atom has fewer electrons than are needed for chemical bonds with neighboring atoms of the host semiconductor. For example, a boron atom has only three electrons available for bonding. Hence, when a boron atom replaces a silicon atom in silicon, it “accepts” one missing electron from the valence band, creating a hole.

How do you find the impurity concentration of a compensated semiconductor?

In a compensated semiconductor, the largest impurity concentration “wins”: if Nd > Na, the compensated semiconductor is n- type with the effective donor concentration, Ndeff = Nd − Na; if Nd < Na, the compensated semiconductor is p -type with the effective acceptor concentration, Naeff = Na − Nd.