Nanostructural analysis of ZnO:Al thin films for carrier-transport mechanisms

The carrier mobility of sputter-deposited Al-doped ZnO transparent-conducting (ZnO:Al) thin films was controlled between 22 and 48 cm2/Vs by varying the ZnO:Al seed layer. The statistical distribution of the [001] grain misorientation was characterized from the X-ray diffraction rocking curve in the range from 0.043 (2.5°) to 0.179 rad (10.2°). The grain-boundary energy barriers (Eb) from Seto's model [1] clearly exhibit linear dependence on the grain-boundary misorientation angle (ω) according to the equation Eb = 78 ± 4 + 173 ± 32 ω meV.

► Carrier mobility of TCO is straightforwardly controlled by the seed-layer variation.
► The grain misorientation is in the range from 0.043 (2.5°) to 0.179 rad (10.2°).
► Transport energy barrier clearly exhibits linear dependence on the misorientation.