Enhanced field emission properties of indium-doped ZnO nanorods

Various group-III metal (Al, Ga, and In)-doped ZnO nanorods were synthesized by a vapor phase deposition in a horizontal reactor. The morphology and optical properties of the group-III metal doped nanorods were compared to determine the best candidate as a donor impurity. Among these three nanorod samples, indium-doped ZnO (ZnO : In) nanorods revealed the best result in terms of uniform morphology, strong luminescence intensity and negligible deep levels. The electrical properties of ZnO:In nanorods with various In-composition were indirectly assessed by Hall-effect measurements of the wetting layer. Also, we found that the ZnO : In nanorods show considerably improved field emission properties in compared to undoped ZnO nanorods with a low threshold electric field (E-th) of 4.32 V/mu m at a current density of 0.1 mu A/cm(2) and a high field enhancement factor of 1258.