Fabrication of Ag/Ag2O/MgO/n-Si/Ag Heterojunction by Laser Ablation in Water for Visible and IR Photodetector
摘要
High-quality film of MgO and Ag2O on n-Si wafers are prepared herein. The structural properties by XRD show that MgO has a cubic structure., whereas the Ag2O film exhibit fcc and cubic structures. The average crystallite size of MgO and Ag2O was (20.25 and 16.58) nm, respectively. From SEM of MgO film has looks like a porous structure with the smallest diameter of MgO being approximately 25.52 nm. while the silver oxide film has the shape of the nanoparticles was oval and spherical togather. Only a few individual particles were observed with the smallest diameter of Ag2O NPs being approximately 19.82 nm., while the majority of the nanoparticles had aggregated to formation large sizes. The AFM images depict MgO silver nanoparticles, which have sizes ranging from approximately 24.96 nm for MgO and 29.47 for Ag2O. These nanoparticles exhibit roughly spherical shapes, with a root mean square (grain-wise) of 4.5 nm for MgO and 8.6 nm for Ag2O. The presence of MgO and the vibration of Ag2O were confirmed by FTIR testing. Based on absorption spectra, the band gaps of MgO and Ag2O are confirmed to be about 5.6 eV and 3.4 eV, respectively. Research gap is to Lack of studies on the use of MgO and Ag2O together in photodetectors, especially when prepared by laser ablation.The research problem is to improve the performance of the photodetector prepared using MgO and Ag2O as deposited layers on silicon, as they work together to improve the spectral response and specific detection, as display the results we have reached. Therefore, a heterostructural photodetector comprising Ag/MgO/n-Si/Ag, Ag/Ag2O NPs/n-Si/Ag and Ag/Ag2O/MgO/n-Si/Ag is assembled. With a bias of –5 V, the peak at 850 nm was 0.36 A/W, indicating that the detector functions in the IR region. In the Ag/Ag2O/MgO/n-Si/Ag sample, a responsivity of 0.25 A/W was observed at short wavelengths of 450 nm and 0.65 A/W at 850 nm. With a value of 5.22 * 10^12 Jones, the detectivity reaches its optimum at 850 nm, which is favorable for Ag/MgO/n-Si/Ag, Ag/Ag2O NPs/n-Si/Ag photodetectors. The detectivity of the Ag/Ag2O/MgO/n-Si/Ag photodetector was measured at 450 nm and found to be 3.64 * 10^12 Jones, while at 850 nm, it was 9.3 * 10^12 Jones.