Hydroxyl black phosphorus crystal based highly symmetric ambipolar transistors for infrared in-sensor encryption

With the increasing demand for infrared sensing data security, it is crucial to enhance the security of sensing data by utilizing in-sensor encryption techniques while simultaneously reducing latency, power consumption, and hardware resource utilization. However, the inherent computational limitations of sensors impede their capacity to execute sophisticated encryption algorithms. In this paper, we propose hydroxyl black phosphorus (BP) crystal for ambipolar transistors that enable infrared in-sensor encryption. An innovative approach utilizes a simple oxygen plasma treatment technique to fabricate hydroxyl BP crystal is proposed. Hydroxyl bonded on the surface of BP shifts the Fermi level towards the conduction band and generates free electrons, results ambipolar transport. The hydroxyl BP transistors exhibit symmetrical bipolar characteristics with hole mobility of 131.4 cm² V⁻¹ s⁻¹ and electron mobility of 89.8 cm² V⁻¹ s⁻¹. Importantly, a non-linear XOR logic gate can be implemented within a single transistor during the infrared sensing process, effectively simplifying the complexity of in-sensor encryption design. Expounding upon this, we demonstrate an infrared in-sensor encryption using an array of hydroxyl BP transistors, which can capture images and achieving high-fidelity infrared in-sensor encryption. Our findings highlight the potential of hydroxyl BP in the development of infrared in-sensor encryption techniques.