Fabrication and characterization of Al/Ca2Nb3O10/p-Si and Al/Ca2Nb3-xTaxO10/p-Si layered perovskite oxide-based heterojunction diodes

Two-dimensional (2D) materials have garnered considerable interest for next-generation semiconductor device development due to their atomic-scale thickness and distinctive electronic, optical, and surface properties. Their high surface-to-volume ratio, low defect density, and tunable band structure render them particularly suitable for fundamental electronic components, such as p-n junction and semiconductor-based diodes. The ability of 2D materials to form vertical heterostructures confers advantages over conventional semiconductor diodes, including lower operating voltages and enhanced photosensitivity. In this study, Schottky type heterojunction diodes based on n-CNO/p-Si and n-CNTO/p-Si heterostructures were fabricated using the layered perovskite oxides KCa2Nb3O10 (CNO) and its tantalum-doped derivative KCa2Nb3-xTaxO10 (x = 1.5; CNTO). CNO and CNTO nanosheets were synthesized via solid-state reaction, proton exchange, and exfoliation, and were subsequently deposited onto p-type silicon substrates by spin coating. Current-voltage (I-V) characteristics of the fabricated diodes exhibited rectification ratios of 3,06 × 106 (CNO) and 4.77 × 106 (CNTO), with corresponding ideality factors of 1.91 and 1.78, respectively. The devices exhibited favorable performance characteristics, including low leakage current and high rectification ratios. In particular, CNTO-based structures demonstrated better electrical performance compared to CNO due to defect engineering facilitated by Ta doping. These findings underscore the promise of CNO and CNTO nanosheets as semiconductor materials for future optoelectronic applications.