The intriguing carrier dynamics in graphene heterojunctions have stimulated great interest in modulating the optoelectronic features to realize high-performance photodetectors. However, for most phototransistors, the photoresponse characteristics are modulated with an electrical gate or a static field. In this paper, we demonstrate a graphene/C₆₀/pentacene vertical phototransistor to tune both the photoresponse time and photocurrent based on light modulation. By exploiting the power-dependent multiple states of the photocurrent, remarkable logical photocurrent switching under infrared light modulation occurs in a thick C₆₀ layer (11 nm) device, which implies competition of the photogenerated carriers between graphene/C₆₀ and C₆₀/pentacene. Meanwhile, we observe a complete positive-negative alternating process under continuous 405 nm irradiation. Furthermore, infrared light modulation of a thin C₆₀ (5 nm) device results in a photoresponsivity improvement from 3425 A/W up to 7673 A/W, and we clearly probe the primary reason for the distinct modulation results between the 5 and 11 nm C₆₀ devices. In addition, the tuneable bandwidth of the infrared response from 10 to 3 × 10³ Hz under visible light modulation is explored. Such distinct types of optical modulation phenomena and logical photocurrent inversion characteristics pave the way for future tuneable logical photocurrent switching devices and high-performance phototransistors with vertical graphene heterojunction structures.

石墨烯异质结中有趣的载流子动力学激发了人们对调制光电特性以实现高性能光电探测器的极大兴趣。然而，对于大多数光电晶体管来说，光响应特性是通过栅极或静态场进行调制的。在本文中，我们展示了一种石墨烯/C ₆₀ /并五苯垂直光电晶体管，可根据光调制调节光响应时间和光电流。通过利用光电流的功率依赖性多态，在厚C ₆₀层（11 nm）器件中发生红外光调制下显着的逻辑光电流切换，这意味着石墨烯/C ₆₀和C ₆₀ /并五苯之间光生载流子的竞争。同时，我们在连续405 nm照射下观察到完整的正负交替过程。此外，薄 C ₆₀ (5 nm) 器件的红外光调制可将光响应率从 3425 A/W 提高到 7673 A/W，并且我们清楚地探究了 5 和 11 nm 之间不同调制结果的主要原因C ₆₀设备。此外，还 探索了可见光调制下从10到3×10 ^{3 Hz的红外响应的可调带宽。}这种不同类型的光调制现象和逻辑光电流反转特性为未来可调谐逻辑光电流开关器件和具有垂直石墨烯异质结结构的高性能光电晶体管铺平了道路。