【会员论文】重庆师大李泓霖/张红/李万俊Materials Today Physics: 非晶Ga₂O₃/Cr₂O₃异质结光电探测器双极性响应及其光电逻辑门与混沌加密光通信

        重庆师范大学李万俊教授团队（宽带隙半导体材料与器件团队）在非晶Ga₂O₃/Cr₂O₃异质结光电探测器双极性响应及其光电逻辑门与混沌加密光通信研究中取得进展。相关成果以“Optoelectronic logic gates and chaotic encryption optical communication enabled by dual-band optical response in a-Ga₂O₃/Cr₂O₃ heterostructures”为题发表在《Materials Today Physics》杂志上。团队研究生岳泉材为第一作者，李泓霖教授、张红副教授和李万俊教授为共同通讯作者。

        自供电双极性光电探测器具有低功耗、低成本与多功能优势，在光电子逻辑门与安全光通信领域前景广阔。然而，传统单极性探测器功能较为单一，限制了其在复杂光电系统中的应用。为此，研究团队采用溶胶-凝胶旋涂结合射频磁控溅射的复合工艺，成功制备出具有Ⅱ型能带排列的a-Ga₂O₃/Cr₂O₃异质结器件。该器件在254 nm（深紫外）光照下产生正光电流，在380 nm（近紫外）光照下产生负光电流，响应时间分别低至82.1/91.2 ms与9.1/13.6 ms，并在3000秒连续测试中保持稳定性能，优于多数已报道的双极性探测器。基于器件独特的双波段双极性响应特性，团队通过调节254 nm与380 nm光源的照射强度与时序，在单一器件中成功实现了“或（OR）”“与（AND）”“或非（NOR）”“非（NOT）”“与非（NAND）”五种基本布尔逻辑运算。进一步地，研究团队构建了基于该探测器的双波段加密光通信系统。该系统将光电化学信号与混沌-XOR加密技术结合，通过建立光学输入状态、归一化光电流响应与DNA碱基序列之间的正交映射关系，实现了高安全性信息传输。实验表明，该系统可准确传输16×16二进制矩阵编码的图像信息，相比传统单极性探测器系统，具备更大的密钥空间与更强的抗截获能力，即便在密钥参数存在微小偏差时仍无法被有效解码，为安全光通信提供了可靠的技术支持。

Figure 1. a) Schematic fabrication process of Cr₂O₃ thin film. b) Heterostructure design of the a-Ga₂O₃/Cr₂O₃ junction. c) Cross-sectional SEM image of a-Ga₂O₃/Cr₂O₃. d) Surface EDS elemental mapping of a-Ga₂O₃/Cr₂O₃. e-g) M–S analysis of a-Ga₂O₃, Cr₂O₃ and a-Ga₂O₃/Cr₂O₃, respectively. h) Raman scattering spectrum of a-Ga₂O₃/Cr₂O₃. i) Ga 2p3/2 XPS spectra of pristine a-Ga₂O₃ and a-Ga₂O₃/Cr₂O₃, showing peak positions at 1118.47 and 1118.50 eV, respectively. j) Cr 2p3/2 XPS spectra of pristine Cr₂O₃ and a-Ga₂O₃/Cr₂O₃, showing peak positions at 576.36 and 576.27 eV, respectively.

Figure 2. a) I-t characteristics of the a-Ga₂O₃/Cr₂O₃ PEC detector under various wavelengths at 0 V bias (500 μW cm⁻²). b) I-t response of the a-Ga₂O₃/Cr₂O₃ PEC detector at 0 V bias under 254 and 380 nm illumination with varying light intensities. c, d) Extracted photocurrent density and responsivity versus light intensity at 254 and 380 nm. e) Response time characteristics at 0 V bias under 254 and 380 nm illumination. f) Comparison of response times with reported PDs. g) Long-term stability test over 3000 s at 0 V under 254 and 380 nm illumination. h) Magnified view of stability performance during 1500–1600 s.

Figure 3. a) Absorption spectrum and optical band gap of a-Ga₂O₃. b) Absorption spectrum and optical band gap of Cr₂O₃. c) Valence-band XPS spectra and Ga 2p core level spectrum of a-Ga₂O₃. d) Valence-band XPS spectra and Cr 2p core level spectrum of Cr₂O₃. e) Ga 2p and Cr 2p core level spectra of a-Ga₂O₃/Cr₂O₃ heterojunction. f) Band alignment diagram of a-Ga₂O₃/Cr₂O₃ heterojunction. g) Plane averaged electronic potential of a-Ga₂O₃ and Cr₂O₃. The inserts show atomic models of two structures. h) Operational mechanism of a-Ga₂O₃/Cr₂O₃ under 254 nm illumination. i) Operational mechanism of a-Ga₂O₃/Cr₂O₃ under 380 nm illumination.

Figure 4. Schematic diagrams of five OELGs implemented using a single self-powered PEC-PD: a) “OR” and “AND” gates using two UV-C inputs under UV-A gate modulations. b) “NOR”, “NOT”, and “NAND” gates using two UV-A inputs under UV-C gate modulations. c) Truth table for five OELGs under four input combinations. d-g) OELGs operations. d) Photocurrent output versus UV-A intensity for UV-C inputs. e) Transient photocurrent curves of “OR” and “AND” gates under UV-C inputs (100 μW cm⁻²) at UV-A intensities of 8, 84, and 256 μW cm⁻², respectively. f) Photocurrent output versus UV-C intensity for UV-A inputs. g) Transient photocurrent curves of “NOT”, “NOR”, and “NAND” gates under UV-A inputs (45 μW cm⁻²) at UV-C intensities of 120, 150, and 340 μW cm⁻² respectively.

Figure 5. a) Schematic of the dual-channel optical communication test setup and detailed encapsulation of the working electrode. b) Matrix obtained after chaotic encryption and XOR processing of the encoded binary matrix. c) Encrypted matrix obtained after chaotic encryption and XOR processing of the binary-encoded matrix. d) Normalized photocurrent response of the a‑Ga₂O₃/Cr₂O₃ photoelectrode under four optical switching states using 254 and 380 nm illumination, demonstrating a direct correspondence to DNA base sequences. e) Conventional unidirectional photoelectrode receiving intercepted DNA-encoded signal: decoded image with missing information. f) Decrypted image matching the original input, achieved using the correct chaotic key and DNA-encoded signals received by the a‑Ga₂O₃/Cr₂O₃ photoelectrode. g) Bipolar photoelectrode receiving intercepted DNA-encoded signal with erroneous chaotic key: decoded image deviating significantly from the original input.

论文信息：

Quancai Yue, Lijuan Ye, Lai Yuan, Guoping Qin, Di Pang, Yan Tang, Honglin Li*, Hong Zhang* and Wanjun Li*.  Optoelectronic Logic Gates and Chaotic Encryption Optical Communication Enabled by Dual-Band Optical Response in a-Ga₂O₃/Cr₂O₃ Heterostructures. Materials Today Physics, 2026, 61: 102032.

论文链接：

https://doi.org/10.1016/j.mtphys.2026.102032.