Enhanced Performance of Gallium‐Based Wide Bandgap Oxide Semiconductor Heterojunction Photodetector for Solar‐Blind Optical Communication via Oxygen Vacancy Electrical Activity Modulation

• Published in: Advanced optical materials 2024-04, Vol.12 (10), p.n/a
• Main Authors: Wu, Chao, Zhao, Tianli, He, Huaile, Hu, Haizheng, Liu, Zeng, Wang, Shunli, Zhang, Fabi, Wang, Qinfeng, Liu, Aiping, Wu, Fengmin, Guo, Daoyou
• Format: Article
• Language: English
• Subjects: alloy engineering; Communications systems; Dark current; Energy gap; gallium oxide; Gallium oxides; Heterojunctions; Optical communication; Oxygen; oxygen vacancy regulation; Performance enhancement; Photoconductivity; Photometers; solar‐blind communication system; solar‐blind photodetector; Thin films
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202302294

Gallium oxide (β‐Ga2O3) is a prominent representative of the new generation of wide‐bandgap semiconductors, boasting a bandgap of ≈4.9 eV. However, the growth process of β‐Ga2O3 materials introduces unavoidable oxygen vacancies (Vo), leading to persistent photoconductivity (PPC), a phenomenon that severely hinders device performance. In this study, an innovative approach is successfully developed by introducing high p‐orbital energy nitrogen (N). This leads to the formation of a hybridized state with O 2p orbitals in β‐Ga2O3, resulting in the creation of GaON and suppressing the electrical activity of Vo. Through meticulous experimentation and advanced computational methods, a comprehensive and insightful explanation of the regulation and mechanism underlying this passivation process is offered. Moreover, pn‐junction solar‐blind photodetectors are engineered using hybridized GaON thin films with p‐type CuPc. These photodetectors demonstrate exceptional characteristics, including ultra‐low dark current (10−14 A), high photo‐to‐dark current ratio (106), and rapid decay speed (0.008 s) even at zero bias. Based on these advancements, a solar‐blind ultraviolet communication system is designed, featuring straightforward and reliable encoding, easy implementation, and robust anti‐interference capabilities. By utilizing the N 2p‐O 2p orbital hybridization, the valence band electron energy band structure is effectively modulated, suppressing the electrical activity of oxygen vacancies and sustaining the photoconductive effect.