Grain boundary related electrical transport in Al-rich Al x Ga1 − x N layers grown by metal-organic chemical vapor deposition

Abstract

Electrical transport data for Al rich AlGaN layers grown by metal-organic chemical vapor dep osition (MOCVD) are presented and analyzed in the temperature range 135-300 K. The temperature depen dence of electrical conductivity indicated that conductivity in the films was controlled by potential barriers caused by carrier depletion at grain boundaries in the material. The Seto's grain boundary model provided a complete framework for understanding of the conductivity behavior. Various electrical parameters of the present samples such as grain boundary potential, donor concentration, surface trap density, and Debye screening length were extracted.

Si doped ZnO thin films for transparent conducting oxides

“…Yildiz et al indicates that the potential barrier height in the films decreased with increasing grain size; on the contrary, the shrinkage of a grain size leads to an increment in the trapping states at a grain boundary. Trapping states are capable of trapping free carriers; as a consequence, more free carriers become immobilised as the density of trapping states increases 26. The decrease in the potential barrier height is also due to increase in crystallite size, resulting in diminishing charge carrier scattering at the grain boundaries.…”

“…Trapping states are capable of trapping free carriers; as a consequence, more free carriers become immobilised as the density of trapping states increases. 26 The decrease in the potential barrier height is also due to increase in crystallite size, resulting in diminishing charge carrier scattering at the grain boundaries. Hence, in region I, the improvement of crystallinity with sputtering time results in a resistivity lowering effect.…”