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

2026-04-10T09:32:19+00:00

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

2026-04-18T06:16:12+00:00

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.

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

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