Comment
Author: Admin | 2025-04-27
Parameter of semiconductors. Impurity level has significant impact on carrier concentration, microstructure and related aspects of a semiconductor. Generally, through doping, the intentional introduction of extra compositions into an intrinsic semiconductor alters the impurity level, resulting in the variation of electrical and optical properties. From the perspective of band theory, doping introduces extra energy levels within the band gap and the introduced energy levels will be closed to valence band or conduction band when species of dopant are different. Specifically, electron donor or n-type doping brings in energy levels near the conduction band while electron acceptor or p-type doping brings in ones near the valence band. As for ZnO, n-type doping can be achieved by replacing with Al, Ga, In and other group-III elements or by substituting group-VII elements for O while p-type doping is commonly thought to be difficult [4, 33, 34]. From point of view of carrier concentration, regardless of n-type or p-type doping, doped semiconductors would have higher carrier concentration compared to their intrinsic state because both electrons in n-type semiconductors and holes in p-type semiconductors contribute to conductivity significantly. Some highly doped semiconductors even possess conductivity comparable to metals. The reason impurity level of semiconductor is importants is that it has a direct impact on the carrier mobility, which is another crucial parameter of semiconductors when they are applied to electronic devices. Carrier mobility is related to two kinds of scattering inside material: lattice scattering (phonon scattering) and ionized impurity scattering [35]. In terms of lattice
Add Comment