Micro light emitting device prepared from sputter deposited thin hafnium oxide film

• A new type of micro LED based on ultra thin amorphous HfO2 is reported.
• Light emission principle is the excitation of the conductive path.
• The mechanism of light emission from the metal oxide thin film is clarified.
• The long lifetime of the new LED is due to the unique dielectric structure.

Micro light emitting devices made of the sputter deposited thin hafnium oxide on a p-type silicon wafer have been fabricated and investigated. The emission spectrum covers the visible to near IR wavelength range. The light intensity is affected by the sample’s post deposition annealing temperature and the applied voltage. Light was emitted due to excitation of conductive paths formed from the breakdown of local weak spots. The long lifetime of the device, e.g., >1000 h continuously operated at atmosphere, is due to the isolation of the dielectric embedded conductive paths from the air. This kind of device can be applied to many products.