In this work, fabrication and characterization of Al/Bi2O3NP s/Si/Al heterojunctionis presented. The bismuth oxide layer was prepared by pulse laser ablation in liquid technique (PLAL) at different laser fluenceand electric field.
The effect of electric field during laser ablation process on the structure and electrical properties of the nanoparticles(NPs)is investigated. Furthermore, the effect of applying electric field during synthesis of Al/Bi2O3NPs/Si/Al on properties of photodetector is demonstrated.
UV-visible measurements showed that a red shift in the absorption spectra of Bi2O3 NPs is obtained with increasing laser ablation fluence.
This can be related to the change of the size of NPs which in turns change the band gap of Bi2O3. Applying electric field during laser ablation of Bi2O3led to increasing the particle size.
The morphological investigation, carried out using atomic force microscopy(AFM), showed that the root mean square roughness is increased after applying electric field.The X-Ray diffraction pattern revealed presence of (002), (102), (130) plane, which belong to Bi2O3 and the full width half maximum (FWHM) decreased with increasing the laser fluence and electric field.
The Fourier transform infrared spectroscopy (FTIR) resultconfirms that the formation of Bi-O bond and the absorption intensity of FTIRis proportional directly to the laser fluence and electric field.
The darkI-V characteristics of Bi2O3NPs/Si heterojunction have been improved under effect of electric field, the ideality factor is decreased, while the rectification ratio is increased.The best junction characterization is obtained for Bi2O3 NPs prepared with (21J/cm2) laserfluence and electric field of (7.5 V/cm).
The spectral responsivity of photodetectorsis increased after applying electric field. Maximum responsivity of (0.5A/W) at (λ=550) nm was obtained for photodetectors prepared using 21J/cm2and electric field of (7.5 V/cm). No shift in peak responsivity was observed after applyingelectric field.
Figures of merit for the fabricated photodetectorswereestimated before and after applying electric field. The photodetectors prepared at(21J/cm2)and electric field of (7.5 V/cm) gave a detectivity (D) of (0.16*1011w-1cm H1/2) at (λ=550) nm. Minority carrier lifetime measurements are strongly depended on laser ablationfluence and electric field.
KEY WORD:PHOTODETECTOR. LASERABLATION IN LIQUID. BISMUTH OXIDE NANOPARTICLES