Optimizing charge transport in hybrid GaN-PEDOT:PSS/PMMADevice for advanced application.

Organic-inorganic hybrid light-emitting devices have garnered significant attention in the last few years due to their potential. These devices integrate the superior electron mobility of inorganic semiconductors with the remarkable optoelectronic characteristics of organic semiconductors. The inquiry focused on analyzing the optical and electrical properties of a light-emitting heterojunction that combines p-type GaN with organic materials (PEDOT, PSS, and PMMA). This heterojunction is an organic-inorganic hybrid. The procedure entailed utilizing a spin-coating technique to apply a layer of either poly(methyl methacrylate) (PMMA) or a mixture of PMMA and poly(3,4ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT: PSS) onto an indium tin oxide (ITO) substrate. Subsequently, different Nd:YAG laser pulses (200, 250, and 300 pulses) were used to administer a GaN inorganic layer onto the prepared organic layer using a pulsed laser deposition approach. Subsequently, the thermal evaporation technique was employed to deposit an aluminum electrode on the top of the organic and inorganic layers, while laser pulses were fine-tuned for optimal performance. The Hall effect investigation verifies the p-type conductivity of the GaN material. The electroluminescence studies confirmed the production of blue light by the GaN-based devices throughout a range of voltage situations, spanning from 45 to 72 V.

Mesoporous Ag@WO3 core-shell, an investigation at different concentrated environment employing laser ablation in liquid.

In this study, silver-tungsten oxide core-shell nanoparticles (Ag-WO3 NPs) were synthesized by pulsed laser ablation in liquid employing a (1.06 µm) Q-switched Nd:YAG laser, at different Ag colloidal concentration environment (different core concentration). The produced Ag-WO3 core-shell NPs were subjected to characterization using UV-visible spectrophotometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive spectroscopy, electrical analysis, and photoluminescence PL. The UV-visible spectra exhibited distinct absorption peaks at around 200 and 405 nm, which attributed to the occurrence of surface Plasmon resonance of Ag NPs and WO3 NPs, respectively. The absorbance values of the Ag-WO3 core-shell NPs increased as the core concentrations rose, while the band gap decreased by 2.73-2.5 eV, The (PL) results exhibited prominent peaks with a central wavelength of 456, 458, 458, 464, and 466 nm. Additionally, the PL intensity of the Ag-WO3-NP samples increased proportionally with the concentration of the core. Furthermore, the redshift seen at the peak of the PL emission band may be attributed to the quantum confinement effect. EDX analysis can verify the creation process of the Ag-WO3 core-shell nanostructure. XRD analysis confirms the presence of Ag and WO3 (NPs). The TEM images provided a good visualization of the core-spherical shell structure of the Ag-WO3 core-shell NPs. The average size of the particles ranged from 30.5 to 89 (nm). The electrical characteristics showed an increase in electrical conductivity from (5.89 × 10-4) (Ω cm)-1 to (9.91 × 10-4) (Ω cm)-1, with a drop in average activation energy values of (0.155 eV) and (0.084 eV) at a concentration of 1.6 µg/mL of silver.

Effect of laser fluence on the optoelectronic properties of nanostructured GaN/porous silicon prepared by pulsed laser deposition.

In this study, the fabrication of nanostructured GaN/porous Si by pulsed laser deposition (PLD) was demonstrated. The porous silicon was prepared using laser-assisted electrochemical etching (LAECE). The structural, optical, and electrical properties of GaN films were investigated as a function of laser fluence. XRD studies revealed that the GaN films deposited on porous silicon were nanocrystalline, exhibiting a hexagonal wurtzite structure along the (100) plane. Spectroscopic property results revealed that the photoluminescence PL emission peaks of the gallium nitride over porous silicon (GaN/PSi) sample prepared at 795 mJ/mm2 were centered at 260 nm and 624 nm. According to topographical and morphological analyses, the deposited film consisted of spherical grains with an average diameter of 178.8 nm and a surface roughness of 50.61 nm. The surface of the prepared films exhibited a cauliflower-like morphology. The main figures of merit of the nanostructured GaN/P-Si photodetectors were studied in the spectral range of 350-850 nm. The responsivity, detectivity, and external quantum efficiency of the photodetector at 575 nm under - 3 V were 19.86 A/W, 8.9 × 1012 Jones, and 50.89%, respectively. Furthermore, the photodetector prepared at a laser fluence of 795 mJ/mm2 demonstrates a switching characteristic, where the rise time and fall time are measured to be 363 and 711 µs, respectively.

Preparation of GaN/Porous silicon heterojunction photodetector by laser deposition technique.

In this work, gallium nitride (GaN) thin film was deposited on porous silicon (PSi) substrate via a pulsed laser deposition route with a 355 nm laser wavelength, 900 mJ of laser energy, and various substrate temperatures raging from 200 to 400 °C. The structural and optical properties of GaN films as a function of substrate temperature are investigate. XRD studies reveal that the GaN films deposited on porous silicon are nanocrystalline with a hexagonal wurtzite structure along (002) plane. The photoluminescence emission peaks of the GaN/PSi prepared at 300 °C substrate temperature are located at 368 nm and 728 nm corresponding to energy gap of 3.36 eV and 1.7 eV, respectively. The GaN/PSi heterojunction photodetector prepared at 300 °C exhibits the maximum performance, with a responsivity of 29.03 AW-1, detectivity of 8.6 × 1012 Jones, and an external quantum efficiency of 97.2% at 370 nm. Similarly, at 575 nm, the responsivity is 19.86 AW-1, detectivity is 8.9 × 1012 Jones, and the external quantum efficiency is 50.89%. Furthermore, the photodetector prepared at a temperature of 300 °C demonstrates a switching characteristic where the rise time and fall time are measured to be 363 and 711 µs, respectively.

Silver decorated lithium niobat nanostructure by UV activation method for silver-lithium niobate/silicon heterojunction device.

Lithium niobite (LiNbO3) nanostructure were successfully synthesized by chemical bath deposition method (CBD) and then decorated with silver nitrate (AgNO3) through UV activation method at different immersion durations (5, 15, 25, 35, and 45 s). The silver nanoparticles (AgNPs) effects on the optical and structural properties were studied and analyzed using various scientific devices and technique. X-ray diffraction (XRD) results showed that all the samples have a hexagonal structure with a maximum diffraction peak at the (012), and the existence of silver atoms could be recognized at 2θ = 38.2° which corresponds to the (111) diffraction plane. The optical absorption of nanocomposites depicted the presence of plasma peak related to silver (Ag) at 350 nm. The estimated energy gap from the optical absorption revealed a reduction in the Eg value from (3.97 eV) to (3.59 eV) with the presence of Ag atom. The Photolumincence (PL) peaks were observed at around 355 nm for pure LiNbO3/Si and 358, 360, 363, 371, 476 nm for different immersion durations respectively, in the visible region of the electromagnetic spectrum. The scanning electron microscopy (SEM) study illustrated that with increasing the immersion time, especially at 45 s, a change in the particle morphology was observed (LiNbO3 NRs structure). Atomic force microscopy (AFM) displayed that the surface roughness decreases from 80.71 nm for pure sample to 23.02 nm for the decorated sample as the immersion time is increased. FT-IR manifested a noticeable increase in the intensity of the peaks of samples decorated with AgNPs. Raman spectroscopy elucidated that the peaks shifted to higher intensity due to the plasmonic effect of Ag nanoparticles. Ag-LiNbO3/Si heterojunction nano-devices were fabricated successfully and enhanced the optoelectronic properties in comparison with the pure LiNbO3/Si heterojunction device.

Variation in efficiency with change in band gap and thickness in thin film amorphous silicon tandem heterojunction solar cells with AFORS-HET.

Numerical simulation of both single and double absorbing layers in amorphous silicon thin film solar cell is performed with the use of AFORS-HET. A single absorbing layer solar cell with both a-SiH and a-SiGeH is designed and compared with a tandem heterojunction solar cell, a-SiC/a-SiH/a-Si(i)/a-SiGeH. Design parameters are investigated, compared and optimized. The maximum efficiency for each single absorbing layer and for a tandem heterojunction thin film solar cell, a-SiC/a-SiH/a-Si(i)/a-SiGeH, is predicted. The results are validated by comparing with two different method of analysis.