A semiconductor is a material whose electrical conductivity at room temperature is between that of a conductor and an insulator1. Semiconductors are typically made of materials such as silicon, which are more conductive than insulators but less conductive than pure conductors. By introducing impurities (doping), the conductivity and other properties of a semiconductor can be changed to meet the specific needs of the electronic components in which it resides. Semiconductors are used in integrated circuits, consumer electronics, communication systems, photovoltaic power generation, lighting, high-power power conversion and other fields