Charge carriers refer to particles or entities that carry an electric charge within a material or substance. In the context of semiconductor physics and electronics, charge carriers are commonly electrons or holes (the absence of an electron in a valence band). These charge carriers are responsible for the flow of electric current through a material when a voltage is applied across it. Understanding the behavior and movement of charge carriers is essential in the design and operation of electronic devices such as transistors, diodes, and integrated circuits. Researchers study charge carriers to better understand the electrical properties of materials and to improve the performance of electronic devices.