Fabrication and performance analysis of a collagen-integrated IGZO thin-film transistor for wide-range piezoelectric pressure biosensing

Biocompatible and biodegradable piezoelectric materials have emerged as compelling candidates for next-generation wearable and implantable sensing devices. However, their integration with oxide thin-film transistors (TFTs) for wide-range pressure detection and extended-gate TFT applications remains largely unexplored. In this work, we successfully developed a transparent, self-gated bio-integrated pressure sensor by incorporating piezoelectric collagen film with amorphous indium-gallium-zinc oxide (α-IGZO) TFT. The pressure-induced piezoelectric voltage generated within the collagen film directly modulates the TFT channel, producing a pressure-dependent drain current independent of any external gate bias. Fabrication parameters were preliminarily optimized, systematically determining that 40 min of radio frequency (RF) magnetron sputtering followed by annealing in a nitrogen (N2) atmosphere (50 sccm) at 400 °C yielded superior characteristics and a carrier mobility of 2.66 cm2/V s. With the incorporation of collagen, the developed bio-integrated sensor showed high-performance operation over an extremely broad pressure range of 0.49–980.86 kPa, achieving maximum responsivities of 16.29% at 98.06 kPa (Configuration I) and 6.55% at 980.86 kPa (Configuration II). Significantly, the results are remarkable and strongly consistent with prior research findings, validating the sensor's reliability and performance. These results emphasize collagen–IGZO integration as a viable and scalable strategy toward realizing transparent, wide-range, and potentially fully biodegradable pressure sensors for advanced biomedical and wearable applications.