Influence of Al doping on random lasing in ZnO nanorods

Abstract

Random lasing was demonstrated from aluminum doped ZnO nanorods fabricated on ITO coated glass substrates using simple chemical deposition technique. Different Aluminum (Al) doping parameters were explored in an attempt to realize low threshold ZnO random lasers. Results confirm threshold was strongly dependent on doping concentration and suggestive of resonant coupling with Al in lowering the threshold by 2 orders of magnitude when compared to undoped ZnO nanorods. Lowest threshold was obtained from ZnO nanorods doped with 10 mM of aluminum, suggesting best doping concentration for ZnO random lasers formed by nanorod array. Results further indicate possibility of controlling random lasing properties by adjusting the doping concentration.

Review of Open Cavity Random Lasers as Laser-Based Sensors

“…Current random lasers have been engineered toward reducing the number of lasing modes. Methods include introducing point defects, controlling absorption, and altering the Mie resonances. − …”

Random lasing behaviour in Al-doped ZnO nanorods

“…However, lowering of the lasing thresholds for advancing in this field is still a challenge. Numerous initiatives to lower the lasing thresholds include using dye-doped polymer films [11]- [13], altering the irradiated laser conditions [14], coupling the random cavity modes with planar microcavity modes [15], employing SnO2 nanowires coated with an amorphous layer [16], doping of Al [17], doping of gold [18], and employing a SiO2 capping layer with ZnO nanorods [19].…”

“…There are two methods to perform doping; in-situ and ex-situ. Our previous work on in-situ doping of Al revealed challenges in increasing the doping percentage whereby the maximum reported limit of doping concentrations was between 0.67 % [17] and 1.72 % [29]. In addition, a number of challenges that arise when employing the in-situ method of doping, include a significant distortion along the growth direction (c-axis) [30], decreased deposition rate [31] and slower growth rate [32].…”

Ex-situ doping of ZnO structures as potential random lasers

“…Both in-situ and ex-situ methods can be conducted. However, the maximum limit of doping concentration for random laser synthesized by CBD using the in-situ doping technique was between 5 mM [10] and 10 mM [4]. By using the ex-situ doping approach, doping concentration can be increased.…”