Electrical characterization of pulsed laser deposited high-k HfO2 nanoparticles on tapered Cu2O nanowires: promising cold cathode applications

• DOI: 10.1007/s10854-021-05460-1
• Publication Date: 2021-03-12T08:02:26Z
• Authors: Sachin R. Suryawa...; Raju T. Shisode; Krishna K. Jagtap; Dattatray J. Late; Sharad S. Suryava...; Mahendra A. More
• Keywords: Pulsed Laser Deposition

Pulsed laser deposition (PLD) experiments were employed to deposit a thin adherent coating of HfO2 nanoparticles on electrochemically synthesized Cu2O nanowires. The as-deposited layer of HfO2 on Cu2O nanowires forms a hierarchical assembly of HfO2–Cu2O. The PLD process parameters were optimized to obtain the desired hierarchical morphology and a plausible growth mechanism has been exemplified based on observed SEM results and pertinent literature survey. In addition, field emission (FE) characteristics of the HfO2–Cu2O hierarchical assembly and pristine Cu2O nanowires were carried out at base pressure of 1 × 10–8 mbar. The HfO2–Cu2O nanowires hierarchical emitter exhibits superior FE behavior in terms of lowering in turn-on and threshold fields, delivery of two-fold higher emission current density at relatively lower applied field, as compared to the pristine Cu2O nanowire emitter. HfO2, despite being a wide band gap semiconductor (WBGS) possessing high dielectric constant, the enhanced FE behaviour is mainly attributed to the morphological aspect of hierarchical structure offering high aspect ratio. Furthermore, similar to other WBGS emitters like diamond, in this case too, low electron affinity is speculated to facilitate field emission. The observed results highlight the potential of PLD in fabricating hierarchical structures of WBGs onto other semiconducting oxide nanostructure for novel applications.