Effect of charged dislocation scattering on electrical and electrothermal transport in n-type InN

Temperature-dependent thermopower and Hall-effect measurements, combined with model calculations including all of the relevant elasticand inelastic-scattering mechanisms, are used to quantify the role of charged line defects on electron transport in n-type InN films grown by molecular-beam epitaxy. Films with electron concentrations between 4 × 1017 and 5 × 1019 cm−3 were investigated. Charged point and line defect scattering produce qualitatively different temperature dependences of the thermopower and mobility, allowing their relative contribution to the scattering to be evaluated using charge neutrality at the measured electron concentration. Both charge state possibilities for the dislocations [positively charged (donors) or negatively charged (acceptors)], were considered. The 100–300 K temperature dependence of the mobility and the 200–320 K temperature dependence of the thermopower can be modeled well with either assumption. The dislocation density was independently measured by plan-view and cross-sectional transmission electron microscopy and corresponds well with the values obtained from transport modeling.