when an electron is displaced in a semiconductor, the hole that's left behind is
positive.
The hole behaves like a positive charge, +e
When an electron is displaced in a semiconductor, the hole that is left behind is known as a "positive charge carrier".
To understand this concept, it's important to note that in semiconductors, there are two types of charge carriers - electrons (negative charge carriers) and holes (positive charge carriers).
Semiconductors have a valence band and a conduction band. The valence band is the highest energy band that is completely filled with electrons, while the conduction band is the band just above the valence band that has empty energy states.
When an electron in the valence band gains enough energy (e.g. due to thermal excitation or absorbing a photon), it can move to the conduction band, leaving behind an "electron vacancy" or a hole in the valence band. This hole can be thought of as a positively charged particle that is created due to the absence of the negatively charged electron.
The displacement of an electron in a semiconductor results in the generation of a hole, which can move through the crystal lattice. These holes can also act as charge carriers, contributing to the overall conductivity of the semiconductor.
In summary, when an electron is displaced in a semiconductor, the hole that is left behind is a positive charge carrier that can move through the material.