溶液法制备的ZnO/Al2O3垂直异质结构IGFET：用于柔性电子器件的高迁移率和光电功能

In the realm of flexible and transparent electronics, ZnO Insulated Gate Field-Effect Transistor (IGFET) is a crucial component for its exceptional material properties including a wide bandgap of 3.37 eV, which also aids in achieving high electron mobility, optical transparency, and compatibility with diverse substrates. ZnO-based IGFET offers significant advantages in domains such as transparent electronics, flexible and wearable devices, flat-panel displays, and high-frequency applications. Also, ZnO is superior in thermal and chemical stability which makes it ideal for power electronic systems. A cost-efficient technique has been adopted and investigated for the fabrication of the device, as the solution-processed dip coating technique delivers a large active area with precise control over the film thickness and surface morphology by altering the key parameters, such as withdrawal speed, solution concentration, and viscosity of the solution. This technique’s scalability and simplicity have made it an attractive choice for fabricating high-quality thin film in research and industrial coatings that require uniform coating over large areas. For the construction of IGFET, the top-contact bottom-gate approach has been preferred with zinc oxide (ZnO) as oxide semiconducting material, while aluminum oxide (Al 2 O 3 ) as dielectric material and pure silver (Ag) as the source and drain materials. The N-type phosphorus-doped silicon substrate has been utilized as the gate electrode for the active fabrication of ZnO IGFET. Al 2 O 3 has been coated in order to isolate the gate electrode from the semiconductor channel. The electrical property of the fabricated ZnO IGFET has been determined by I–V characteristics and the field-effect mobility is calculated by implementing channel length and width as 7.35 cm 2 V −1 s −1 such that the post-annealed fabricated IGFET shows a field-effect mobility of 9.25 cm 2 V −1 s −1 , while the subthreshold slope is calculated as 0.286 V/decade before annealing. The post-annealed IGFET shows a subthreshold slope of 0.298 V/decade and the threshold voltage is obtained to be 0.148 V before annealing while the post-annealing results in the threshold voltage is about 0.175 V. The fabricated device has been analyzed in two different light conditions for electrical characterization to evaluate the dependability of the manufactured device, which shows photoresponsivity that can be opted for optoelectronic devices. In order to study the optical properties, UV–visible and photoluminescence studies have been carried out, and the fabricated device is identified to be suitable for optoelectronic devices because of the obtained wider band gap of ZnO. Hall measurements have been demonstrated to calculate the Hall carrier mobility and Hall carrier density and it is given as 6.02 cm 2 eV −1 s −1 and 3.15 × 10 23 cm −3 , respectively. In order to analyze the material’s structural, compositional, and topographical properties, X-ray diffraction and X-ray photoelectron spectroscopic studies have been performed, confirming that the deposited materials could also be identified. Atomic force microscopy and field emission scanning electron microscopy have been employed to evaluate the surface morphology of the fabricated device.