Polarimetric Three-Dimensional Topological Insulators/Organics Thin Film Heterojunction Photodetectors.

As a state of quantum matter with insulating bulk and gapless surface states, topological insulators (TIs) have huge potential in optoelectronic devices. On the other hand, polarization resolution photoelectric devices based on anisotropic materials have overwhelming advantages in practical applications. In this work, the 3D TIs Bi2Te3/organics thin film heterojunction polarimetric photodetectors with high anisotropic mobility ratio, fast response time, high responsivity and EQE in broadband spectra are presented. At first, the maximum anisotropic mobility ratio of the Bi2Te3/organics thin film can reach 2.56, which proves that Bi2Te3 can serve as a sensitive material for manufacturing polarization photoelectric devices. Moreover, it is found that the device can exhibit a broad bandwidth and ultrahigh response photocurrent from visible to middle wave infrared spectra (405 nm ~ 3500 nm). The highest responsivity (Ri) of optimized devices can reach up to 23.54 AW-1, surprisingly, the Ri of the device can still reach 1.93 AW-1 at 3500 nm. In addition, the ultrahigh external quantum efficiency (EQE) is 4534 % with fast response time (1.42 ms). Excellent properties mentioned above indicate that TIs/organics heterojunction devices are suitable for manufacturing high-performance photoelectric devices in infrared region. KEYWORDS: Photodetector, Bi2Te3 thin film, inorganic/organics heterojunction, polarization-resolved, MWIR photodetectors.