A two-band analysis of electrical transport in n-type GaN epilayers

Hall mobilities and Hall coefficients were measured as a function of temperature from 10 to 800 K on Si-doped n-type GaN epilayer grown by metalorganic chemical vapor deposition. Numerical method was adopted for the solution of Boltzmann transport equation with various scattering mechanism to analyse the electron behavior in the Gamma band. The electron transport only in single band, the Gamma band, is dominant at high temperatures. The impurity band conduction, however, has to be added to understand experimental data at low temperatures, resulting in a two-band phenomena.