N-ion-implanted ZnO microtubes for highly-efficient UV detection

Abstract

Here we report a N-ion-implanted ZnO microtube fabricated by optical vapor supersaturated precipitation (OVSP) and ion implantation techniques. The N ions with concentration of ∼2.4 × 1023 cm−3 were mainly located below 100 nm of the surface in the acceptor-rich ZnO (A-ZnO) microtubes. Due to the presence of N in ZnO lattice as NO defects, an ∼15-fold enhancement of near-band edge (NBE)/deep-level emission (DLE) intensity ratio was achieved. The yellow luminescence and the anomalous negative thermal quenching (NTQ) effect further confirmed the NO defect level of 1.3 eV above the valence band maximum in A-ZnO:N microtubes. The implantation of N ions can expand the depletion layer between A-ZnO:N detector and atmospheric species, by which fast photoresponse down to 0.1 s was realized by a metal-semiconductor-metal (MSM) UV detector. Compared with the A-ZnO UV detector, the photoresponsivity of the MSM UV detector was enhanced by ∼10 folds. This work opens up new opportunities to design effective UV detectors for a variety of practical applications.