NIR Laser direct writing at micro-nano-scale of Electronic materials from Metal-Oxo Clusters (MOC) – NIRTRONIC

One of the main innovations relies on the amorphous metal oxides microstructures preparation. To achieve at the same time direct write process and suitable semi-conductor properties, we propose Near-InfraRed (NIR) laser irradiation to prepare in situ, in one-step, at room temperature the semi-conducting micro-nano-structures. The main advantage of NIR curing is that metal oxide material can be obtained at room temperature, which means that the structures can be fabricated on flexible plastic substrates or textiles. The solution-based materials associated to laser-processing makes this disruptive route a very suitable platform for fabrication of low-cost high-performance sensing devices. A functional hydrogel will be coupled to the active metal-oxide material to achieve the salivary urea sensor.

NIR fabrication of electrical on plastic substrates
A metal-oxide material (indium zinc oxide [IZO]) device with near-infrared (NIR) laser annealing was demonstrated on both glass and bendable plastic substrates (polycarbonate, polyethylene, and polyethylene terephthalate). After only 60 s, the sheet resistance of IZO films annealed with a laser was comparable to that of thermal-annealed devices at temperatures in the range of 200-300 °C (1 h). XPS, ATR, and AFM were used to investigate the changes in the sheet resistance and correlate them to the composition and morphology of the thin film. Finally, the NIR-laser-annealed IZO films were demonstrated to be capable of detecting changes in humidity and serving as a highly sensitive gas sensor of hydrogen sulfide (in ppb concentration), with room-temperature operation on a bendable substrate.

Photodetector fabricated by NIR laser
We developed a new process to fabricate indium-zinc-oxide (IZO) with gold nanoparticles (Au NPs) photodetector (PD). The whole process is based on laser annealing using near infrared (NIR), which makes this process suitable for integration of the device on fragile substrates such as thin glass substrates, plastic sheets or even 3D printed pieces. Good photoresponsivity at 410 nm (UV, >100) was demonstrated, but interestingly, the presence of the Au NPs greatly improves the detecting ability to longer wavelength range, such as 515 nm (green, ~5×10-3 A/W), even extend to 630 nm (red, ~5×10-4 A/W) and 780 nm (NIR, ~10-4 A/W). Besides, with the critical evaluation of dynamic light detection and lifetime trace (~1 month), the laser annealed Au NPs/IZO PD can finally perform convincible operating reliability and stability.

To come

1. Chang, P.-Y.; Lin, C.-F.; El Khoury Rouphael, S.; Huang, T.-H.; Wu, C.-M.; Berling, D.; Yeh, P.-H.; Lu, C.-J.; Meng, H.-F.; Zan, H.-W.; Soppera, O., Near-Infrared Laser-Annealed IZO Flexible Device as a Sensitive H2S Sensor at Room Temperature. ACS Applied Materials & Interfaces 2020, 12 (22), 24984-24991.
2. Lin, Y. T.; Yu, S. Y.; Zan, H. W.; Yeh, P. H.; Lu, C. J.; Meng, H. F.; Luo, C. W.; Soppera, O., Photo-assisted recovery in ammonia sensor based on organic vertical diode. Org. Electron. 2019, 67, 272-278.
3. Lin, C.F., Zan H.W., Soppera, O. A novel full laser processed Au NPs/IZO photodetector with wide range detecting demonstrations, submitted to Adv. Photonic Mater.

In the emerging IoT (Internet of Things) era, the wireless communication platform is expected to deliver new critical functions such as the real-time detecting of the key biochemical signal to establish the personal medical database through the big-data computation. The development of miniaturized and wearable devices for personalized and preventive medicine drives a great progress in sensor and analytical chemistry research. New challenges include a requirement for scaling down devices with micro/nanostructures, integrating the on-chip electronic systems with low power consumption, collecting and transmitting the sensing data through a wireless system, etc.
To detect the biomarker in low concentration, sensors with micro/nanostructure is particularly important. The increased surface-to-volume ratio greatly enhances the sensitivity and lowers down the minimum detection limit. Simple solid-state devices with nanostructure or unique nanomaterial compositions can sense the critical breath markers down to a few particles per billion. Prior works, including the work of Prof. Zan, demonstrated that breath ammonia for hemodialysis patients correlates to the key parameter, blood urea nitrogen.
The aim of NIRTRONIC project is developing new fabrication processes for advanced miniaturized (bio)sensors that will be useful for human being monitoring. We propose a technology that is based on solution process and laser curing for micro and nanopatterning. Such process will be used to fabricate field effect transistors (FET) and photodetectors (PD) that will be used for designing biosensors as end-product. We target a specific application that is a sensor for salivary urea, a key factor for chronic kidney disease patients.
One of the main innovation relies on the amorphous metal oxides microstructures preparation. To achieve at the same time direct write process and suitable semi-conductor properties, we propose Near-InfraRed (NIR) laser irradiation to prepare in situ, in one-step, at room temperature the semi-conducting micro-nano-structures. The main advantage of NIR curing is that metal oxide material can be obtained at room temperature, which means that the structures can be fabricated on flexible plastic substrates or textiles. The solution-based materials associated to laser-processing makes this disruptive route a very suitable platform for fabrication of low-cost high-performance sensing devices. A functional hydrogel will be coupled to the active metal-oxide material to achieve the salivary urea sensor.
NIRTRONIC project combines high level scientific and technological challenges, on several aspects: i) Chemistry of materials, photochemistry and ii) fabrication and evaluation of microsensors. This project will be led in collaboration between two teams that are each recognized at the international level for their research activities: The French team at IS2M is specialist of sol-gel materials, photochemistry and micro-nano-fabrication and will thus have in charge the development of the photopatternable semi-conductor material. The Taiwanese team at NCTU will investigate the electrical property of oxide materials by fabricating field-effect transistor (FET), photo detector (PD) and prototype of urea sensor.
The international project is a unique chance to gather the scientific expertise of 2 renewed teams. The benefit for the French team to have a Taiwanese partner is to open possibilities to apply the concept to industrial application thanks to the dynamic microelectronic industry in Taiwan with whom Prof Zan have already contacts and collaboration. Licence of exploitation and/or further collaboration program will be envisaged in the last year of the project. NIRTRONIC project constitutes a unique chance to strengthen the fruitful collaboration between Prof. Zan and Dr Soppera teams initiated ca 10 years ago.