Thickness dependent dislocation, electrical and optical properties in InN films grown by MOCVD
厚度对MOCVD生长InN薄膜位错特性与光电性质的影响

InN thin films with different thicknesses are grown by metal organic chemical vapor deposition, and the dislocations, electrical and optical properties are investigated. Based on the model of mosaic crystal, by means of X-ray diffraction skew geometry scan, the edge dislocation densities of 4.2×1010cm-2 and 6.3×1010cm-2 are fitted, and the decrease of twist angle and dislocation density in thicker films are observed. The carrier concentrations of 9×1018cm-3 and 1.2×1018cm-3 are obtained by room temperature Hall effect measurement. VN is shown to be the origin of background carriers, and the dependence of concentration and mobility on film thickness is explained. By the analysis of S-shape temperature dependence of photoluminescence peak, the defects induced carrier localization is suggested be involved in the photoluminescence. Taking both the localization and energy band shrinkage effect into account, the localization energies of 5.05meV and 5.58meV for samples of different thicknesses are calculated, and the decrease of the carrier localization effect in the thicker sample can be attributed to the reduction of defects.