Influence of implantation assisted Ni doping on structural and optical properties of WO2.72 films

In this paper, structural and optical properties of WO2.72 thin films implanted by 150 keV Ni ions having ion fluences in the range of 1015 to 1016 ions/cm2 have been investigated. Structural investigations (Raman and XRD) suggest the formation of the crystalline monoclinic phase of pristine films. However, after ion implantation, the crystalline quality degrades as a function of ion fluences, and complete amorphization is observed at highest fluence. Further, the bandgap decreases upon ion implantation as a result of band tailing effect. Optical inves-tigation under UV excitation delineates the existence of NUV, band-to-band transition and blue green emission bands in WO2.72 thin films. Implantation-assisted Ni doping blueshifted the new NUV emission peaks due to the enhancement in free electron concentration in the conduction band (CB). The overall hue of the emitted light investigated using Commission International de l'Eclairage (CIE) diagram demonstrates the transition from light to deep blue region upon Ni implantation.

Automated summary

This paper investigates the structural and optical properties of WO2.72 thin films implanted with 150 keV Ni ions at ion fluences ranging from 1015 to 1016 ions/cm2. The structural analysis reveals the formation of a crystalline monoclinic phase in the pristine films, but ion implantation leads to a degradation in crystalline quality and complete amorphization at higher ion fluences. Additionally, the bandgap decreases due to the band tailing effect caused by ion implantation. Optical investigation demonstrates the presence of near ultraviolet (NUV), band-to-band transition, and blue-green emission bands in the WO2.72 thin films. Ni doping through implantation causes a blue shift in the NUV emission peaks, attributed to an increase in free electron concentration in the conduction band. The overall color of the emitted light transitions from light blue to deep blue upon Ni implantation, as demonstrated by the Commission International de l'Eclairage (CIE) diagram.