NanoNEXT

Aluminium-Doped Pbs Thin Films Deposited by Nebulizer Spray Pyrolysis: Structural, Optical, and Photovoltaic Properties

Rigana Begam M, Elavarasan S, Arulanantham A.M.S — Fri, 10 Apr 2026 00:00:00 +0000

Aluminium-doped lead sulfide (PbS) thin films were deposited on glass substrates by using a low-cost nebulizer spray pyrolysis (NSP) method for photovoltaic applications. The Aluminium content was varied from Pure to 5 Wt.% to study its effect on structural, surface, optical, and electrical properties. X-ray diffraction results confirm the formation of polycrystalline PbS with a cubic crystal structure. The films show a strong preferential orientation along the (200) plane. The crystallite size ranges between 18 and 20 nm and changes slightly with doping level. Optical studies show a clear increase in direct band gap from 1.54 eV for the Pure PbS film to 1.66 eV for the 5 Wt.% Al-doped PbS film. This shift indicates a modification in electronic structure and defect states resulting from Aluminium incorporation. Electrical analysis shows lower resistivity and higher carrier concentration at 2.5 Wt.% Al doping. The results indicate that controlled Al doping improves the optoelectronic behaviour of PbS thin films and makes them suitable for low-cost solar cell applications.

Electrical Field Engineering of a Metal Capping Layer for Enhanced Oxide Thin-Film Transistor Performance

Balaji M — Sat, 18 Apr 2026 00:00:00 +0000

Amorphous silicon zinc tin oxide (a-SZTO) thin-film transistors (TFTs) were fabricated and systematically investigated by varying the oxygen flow parameter (OFP) during channel deposition and the metal capping (MC) width on the device structure. The a-SZTO active layer was deposited by RF sputtering, while Ti/Al was used as the source/drain electrode and metal capping layer. The effects of OFP and MC width on the electrical performance of the TFTs were analyzed through current-voltage measurements, including field-effect mobility (µFE), threshold voltage (V_th), subthreshold swing (SS) and total trap density (N_T). For uncapped devices, increasing the OFP from 0 to 10 sccm reduced µ_FE from 14.53 to 8.85 cm²/Vs and shifted V_th from 3.68 to 7.31 V, while SS improved from 0.78 to 0.66 V/decade and N_T decreased from 3.41 to 2.09 × 10¹² cm^-2eV^-1. These results indicate that higher oxygen incorporation suppresses oxygen-vacancy-related donor states and reduces trap density but also lowers the free carrier concentration in the channel. In contrast, the introduction of the Ti/Al metal capping layer increased µ_FE and shifted V_th in the negative direction for all OFP conditions, confirming enhanced electron injection from the capping layer into the a-SZTO channel. At an OFP of 10 sccm, µ_FE increased from 8.85 to 11.02 cm²/Vs and V_th shifted from 7.31 to -1.18 V as the MC width increased from 0 to 40 µm. The transfer-characteristic trends were also consistent with the output characteristics, further verifying that OFP and MC width strongly influence carrier concentration and channel conductivity.

Emerging Two-Dimensional Nanomaterials for Advanced Sensing Applications and Intelligent Systems Integration

Akash Kumar — Tue, 12 May 2026 00:00:00 +0000

Two-dimensional (2D) nanomaterials have emerged as a transformative class of materials, particularly for advancing advanced sensing technologies. The isolation of graphene in 2004, the complex of atomic-level thin materials has expanded rapidly to include MXenes, transition metal dichalcogenides (TMDs), black phosphorus, and crystalline porous frameworks such as metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). These materials show exceptional physicochemical properties, including atomic-scale thickness, very high surface-to-volume ratios, tunable electronic band structures, and extraordinary charge carrier mobility. Such features enable strong interfacial interactions between sensing surfaces and target analytes, helping highly sensitive detection platforms capable of finding ultra-low concentrations of chemical and biological species. The structural characteristics of 2D materials ensure that a huge proportion of atoms are exposed at the surface, promoting efficient adsorption of analyte molecules and inducing pronounced changes in electronic, electrochemical, or optical properties. Therefore, sensing mechanisms based on electrical signal modulation, electrochemical redox reactions, and optical responses can detect minute variations in analyte concentration. Recent advances in synthesis techniques, including liquid-phase exfoliation, electrochemical exfoliation, and chemical vapor deposition, have enabled the fabrication of high-quality 2D nanostructures with controlled thickness and morphology. Also, advanced materials engineering strategies such as heterostructure formation, defect engineering, and surface functionalization have greatly improved sensor sensitivity, selectivity, and stability. This review provides a comprehensive overview of emerging 2D nanomaterials for next-generation sensing technologies. Fundamental sensing mechanisms and recent applications in biomedical diagnostics, environmental monitoring, and chemical detection are systematically discussed. Meanwhile, key challenges related to material stability, large-scale manufacturing, and real-world deployment are detailed, along with future research directions, followed by intelligent sensing systems integrated with artificial intelligence and Internet-of-Things (IoT) technologies.