Hardware-intrinsic secure optical communication via bias-gated bipolarity in a MoS2/α-Ga2O3 heterostructure

Reconfigurable optoelectronic logic devices are essential for advancing in-sensor computing and secure optical communication. Herein, we report a bias- and wavelength-co-regulated bipolar photoelectrochemical device based on a MoS 2 / α -Ga 2 O 3 heterojunction, fabricated by hydrothermally growing α -Ga 2 O 3 nanorod arrays and subsequently depositing MoS 2 nanospheres via chemical vapor deposition, thereby extending the spectral response into the middle-wave ultraviolet regime. Systematic characterizations reveal that the device exhibits fast response speed and pronounced voltage-tunable polarity inversion. At −0.2 V, 254 nm illumination generates a negative photocurrent, whereas 295 nm produces a positive one; under dual-wavelength illumination, these components cancel completely, restoring the dark current. Energy band analysis attributes this behavior to synergistic carrier dynamics at the dual α -Ga 2 O 3 /electrolyte and MoS 2 / α -Ga 2 O 3 interfaces. Exploiting this mechanism, we achieve reconfigurable AND, OR, and XOR logic functions within a single device solely via bias control. Furthermore, a physical-layer-secure optical communication strategy is demonstrated, employing a constant dual-wavelength power envelope to thwart eavesdropping and bias voltage as a hardware decryption key. This work offers a promising pathway toward compact, low-power, intelligent systems for secure underwater communication and optical computing.