Majority and minority charge carriers:

Charge carriers in the semiconductor materials are either electrons, which have unit negative charge, or holes, having unit positive charge. In any of the semiconductor material, some current is in the form of electrons passed from atom to atom in the negative to positive direction. Some current occurs as holes which move from atom to atom from positive to negative direction.

At times electrons dominate the current flow in the semiconductor;  this is case if the material has donor impurities. In the substances having acceptor impurities, then the holes dominate. The dominating charge carriers are the majority carriers. The less abundant ones are called as minority carriers.

The ratio of majority to minority carriers can vary, depending upon the nature of semiconducting material.

Electron flow

In the N-type semiconductor, most of the current flows in the form of electrons passed from atom to atom. But some current in the P-type material also takes this form It would be a good idea to turn back for a moment and review this material, as it will assist you to understand concept of hole flow.

Hole flow

In the P type semiconductor, mostly the current flows in a way that some people find peculiar and esoteric.  Virtually all the electronic device, charge transfer is the result of electron movement, regardless of the medium it has. The exceptions are particle accelerators and cloud chambers apparatus of interest majorly to theoretical physicists.

The flow of current in the P-type material is imagined as the flow of electron absences, not electrons. The behavior of P-type substances is explained more easily in this manner. The absences, called as holes, move in the direction opposite that of the electrons.

Suppose a sold out baseball stadium. Let19 of every 20 people are issued candles randomly. Imagine it is a nighttime, and field lights are switched off. You stand at center of the field, behind second base. The candles are lit, and people pass them around the stands. Each person having the candle passes it to the person to the right if, that person has no candle. You see moving some dark spots: people without candles. The dark spots move against the movement of candle. The physical image you see is generated by candle light, but the motion you notice is of candles absences. Figure given to us illustrates this phenomenon. The small dots represent candles or electrons. Imagine them moving from right to left in figure as they are passed from person to person. The circles represent candle absences or holes. They move from left to right, contrary to flow of candles or the electrons, as the candles or electrons are being passed among stationary units. This is similar to the way holes flow in the semiconductor material.