Waveguide-integrated graphene photodiodes are on-chip optoelectronic devices with promising applications in telecommunications. Here, we present the electrical properties of a heterostructure consisting of multilayer graphene (MLGr) over a Si waveguide covered by an ultrathin Al₂O₃ layer. The waveguide is fabricated by etching a silicon-on-insulator (SOI) substrate with 220 nm Si and 1.5 μm buried oxide. The 5 nm-thick Al₂O₃ film is deposited by atomic layer deposition (ALD), while graphene, synthesized on copper by chemical vapor deposition (CVD), is transferred onto the Al₂O₃/Si rib by a wet transfer method. The MLGr/Al₂O₃/Si rib forms a Schottky structure with rectifying current–voltage characteristics, which are examined using the thermionic emission theory and Norde’s method. A Schottky barrier height \({\Phi }_{{\text{B}}} = 0.79\mathrm{ eV}\), an ideality factor n = 26, and a series resistance \({{\text{R}}}_{{\text{S}}} = 11.6\mathrm{ M\Omega }\) are obtained. The device is promising for operation at the optical fiber communication wavelength of 1550 nm.

波导集成石墨烯光电二极管是片上光电器件，在电信领域具有广阔的应用前景。_{在这里，我们展示了由超薄 Al 2} O ₃层覆盖的硅波导上的多层石墨烯 (MLGr) 组成的异质结构的电学特性。该波导是通过蚀刻具有 220 nm Si 和 1.5 μm 埋层氧化物的绝缘体上硅 (SOI) 基板来制造的。通过原子层沉积（ALD）沉积5 nm厚的Al ₂ O ₃薄膜，而通过化学气相沉积（CVD）在铜上合成的石墨烯通过湿转移方法转移到Al ₂ O ₃ /Si肋上。MLGr/Al ₂ O ₃ /Si肋形成具有整流电流-电压特性的肖特基结构，使用热电子发射理论和Norde方法对其进行了检验。肖特基势垒高度\({\Phi }_{{\text{B}}} = 0.79\mathrm{ eV}\)、理想因子 n = 26 和串联电阻\({{\text{R}得到}}_{{\text{S}}} = 11.6\mathrm{ M\Omega }\) 。该器件有望在 1550 nm 光纤通信波长下运行。