Efficient Field Emission from Vertically Aligned Cu2O1-δ(111) Nanostructure Influenced by Oxygen Vacancy

In the architecture described, cuprous oxide (Cu2O) is tamed to be highly (111) plane oriented nanostructure through adjusting the deposition postulate by glancing angle deposition technique. In the controlled atmosphere oxygen vacancy is introduced into the Cu2O crystal subsequently fostering an impurity energy state (E-im ) close to the conduction band. Our model of Cu2O electronic structure using density functional theory suggests that oxygen vacancies enhance the electron donating ability because of unshared d-electrons of Cu atoms (nearest to the vacancy site), allowing to pin the work function energy level around 0.28 eV compared to the bulk. This result is also complemented by Kelvin probe force microscopy analysis and X-ray photoelectron spectroscopy method. Oxygen vacancy in Cu2O (Cu2O1-delta) exhibits promising field emission properties with interesting field electron tunneling behavior at different applied fields. The films show very low turn-on and threshold voltages of value 0.8 and 2.4 V mu m(-1) respectively which is influenced by the oxygen vacancy. Here, a correlation between the work function modulation due to the oxygen vacancy and enhancement of field emission of Cu2O1-delta nanostructure is demonstrated. This work reveals a promising new vision for Cu2O as a low power field emitter device.