Wafer‐Scale Bi ₂ O ₂ Se‐on‐Insulator Thin Films for Integrated Electronics

ABSTRACT Quasi‐2D semiconducting Bi 2 O 2 Se has emerged as a promising candidate for beyond‐silicon electronics due to its outstanding transport performances. However, large‐area growth of high‐quality Bi 2 O 2 Se films, which is a critical prerequisite for batch fabrication of electronic devices, remains challenging. Here, we report that wafer‐scale growth of Bi 2 O 2 Se thin films with controllable thicknesses can be achieved on 2‐inch insulating sapphire substrates via quasi‐van der Waals epitaxy using magnetron sputtering. The obtained films show good spatial uniformity and crystallinity across the wafer, enabling massive fabrication of top‐gated Bi 2 O 2 Se/HfO 2 thin film transistors (TFTs) with reliable n‐type enhancement‐mode performances, including positive threshold voltages of ∼1.95 V, field‐effect mobilities of ∼7.15 cm 2 V −1 s −1 , high on/off current ratios of ∼10 5 , and subthreshold swings of 1.4 V/dec. The integrated inverter, NAND, and NOR logic gates show desired functionalities with high voltage gains of ∼24.7. This study represents a significant step toward the real application of Bi 2 O 2 Se in TFT display technology and complex integrated electronics in a low‐cost, scalable, and industry‐compatible manner.