2D Porous ZnO Nanosheets: One Pot Synthesis with Low Turn-on Field

Low turn-on field of 2.3 V/µm was found for the emission current density of 10 µA/cm2 from 2D porous ZnO nanosheets. High current density of 0.76 mA/cm2 was drawn at an applied field of 4.1 V/µm. The observed low turn-on field of porous ZnO nanosheets has been found to be superior to the other ZnO nanostructures reported in the literature. Also, the emission current stability over a period of 3 hr is found to be better. The field emission current density-applied field (J-E) and current-time (I-t) measurements were carried out in all metal field emission microscope by using ‘close proximity’ (also termed as ‘planar diode’). The porous ZnO nanosheets were synthesized by Chemical Bath Deposition (CBD) method at room temperature followed by annealing at 200 oC. The annealed ZnO nanosheets were subjected to structural and morphological analysis prior to the field emission studies. The XRD spectrum of the as-synthesized product reveals formation of crystalline hexagonal phase of ZnO. Simple synthesis route with superior field emission properties indicate the possible use of porous ZnO nanosheets for micro/nanoelectronic devices.