Micromachines

Zinc(II) bis(8-hydroxyquinolinate) (Zn(HQ)₂) and 1,10-phenanthroline (phen) were combined to fabricate an organic semiconductor in a bulk heterojunction architecture and subsequently embedded in a poly 3,4-ethylene dioxythiophene–polystyrene sulfonate (PEDOT–PSS) matrix. The resulting Zn(HQ)₂-phen/PEDOT–PSS was deposited as a film upon tin-oxide-coated glass and graphite-covered Tetra Pak (TP)-recycled substrates for the manufacture of organic photoconductive devices. The topographical and micromechanical characteristics of the hybrid films were assessed by atomic force microscopy, with an average roughness of 5.6 nm, maximum tensile strength of 7.95 MPa, and Knoop microhardness of 14.7. The fundamental energy gap (E_g) was determined employing the Kubelka–Munk function, with E_g of 3.5–3.8 eV. These results were complemented with a computational DFT molecular orbital analysis of the species involved in the hybrid semiconductor. The devices were electrically characterized under UV irradiation conditions, obtaining the current–voltage and power–voltage relationships. The maximum current in the TP–graphite device is 1.8 × 10⁻² A and 1.1 × 10⁻² A in the device on glass–ITO. Zn(HQ)₂-phen/PEDOT–PSS film presents its own operating regimes relating to a photoconductor or flexible photoresistor. The power in the device on glass–ITO is 120 mW and 113 mW for shortwave and longwave, respectively, and in the device on TP–graphite, it is 198 mW and 139 mW.

Externally applied electric fields are widely employed during thin-film deposition to improve film uniformity, texture and densification. Despite extensive experimental evidence, the physical mechanisms by which such fields influence nucleation, surface diffusion, island coalescence and interface stability remain theoretically fragmented. Classical thin-film growth models assume a field-free energetic landscape and therefore provide limited predictive guidance for field-assisted manufacturing strategies. In this work, we introduce the Field-Driven Growth Model (FDGM), a unified theoretical framework that incorporates field–matter interactions directly into the free-energy functional governing thin-film growth. By explicitly accounting for effective dipolar coupling arising from field-induced polarization of surface species, predominantly quadratic in the field amplitude and consistent with linear-response polarization, the model consistently modifies the fundamental processes of nucleation, surface diffusion and coalescence. At the continuum scale, the FDGM predicts a field-induced stabilization mechanism that suppresses long-wavelength roughening modes and defines a field-controlled morphological crossover wavelength (field-controlled cutoff). The FDGM demonstrates that field-assisted nucleation bias, anisotropic surface diffusion, field-biased coalescence pathways and morphological stabilization are not independent phenomena, but multiscale manifestations of a single energy-minimization principle acting on a field-modified energy landscape. By providing analytical stability criteria and explicit links between external field parameters and morphological outcomes, the model establishes a predictive foundation for the manufacturing of thin films with improved uniformity in advanced thin-film-based devices. The framework is broadly applicable to deposition techniques such as sputtering, pulsed-laser deposition, chemical vapor deposition and atomic layer deposition.

This work presents a millimeter-wave half-mode substrate integrated waveguide filter with high selectivity, using through glass via technology. Compared to a traditional printed circuit board, the benefits of high precision and integration afforded by the glass-based process enable the substrate-integrated waveguide to be employed at a higher operating frequency. A novel negative coupling structure is proposed for achieving a quasi-elliptic function response, and its coupling mechanism is investigated to explore the properties of the finite transmission zeros. The proposed coupling slots allow for flexible adjustment of the coupling between the half-mode substrate integrated waveguide cavities from positive to negative by modulating the corresponding geometrical parameters. As a prototype, a glass-based fourth-order bandpass filter is synthesized, simulated, fabricated and measured. Subsequently, good matching is captured, confirming the validity of the topology. The proposed glass-based negative coupling structure is promising for realizing substrate integrated waveguide filters with a quasi-elliptic function response, especially operating at millimeter-wave band.