P-type ZnO thin films achieved by N~+ ion implantation through dynamic annealing process

摘要

ZnO thin films were grown on sapphire (0001) substrates by pulsed-laser deposition at 700℃. 70 keV N~+ ion implantation was performed under various temperatures and fluences in the range of 300-460℃ and 3.0 × 10~(14)-1.2 × 10~(15)cm~(-2), respectively. Hall measurements indicate that the ZnO films implanted at 460 ℃ are p-type for all fluences used herein. Hole-carrier concentrations lie in the range of 2.4 x 10~(16)-5.2 × 10~(17)cm~(-3), hole mobilities in the range of 0.7-3.7cm~2 V~(-1) s~(-1), and resistivities between 18-71Ωcm. Transmission-electron microscopy reveals major microstructural differences between the n-type and p-type films. Ion implantation at elevated temperatures is shown to be an effective method to introduce increased concentrations of p-type N dopants while reducing the amount of stable post-implantation disorder.