Three-Dimensional Topological Insulator Bi₂Te₃/Organic Thin Film Heterojunction Photodetector with Fast and Wideband Response from 450 to 3500 Nanometers

Abstract

In the pursuit of broadband photodetection materials from visible to mid-IR region, the fresh three-dimensional topological insulators (3D TIs) are theoretically predicted to be a promising candidate due to its Dirac-like stable surface state and high absorption rate. In this work, a self-powered inorganic/organic heterojunction photodetector based on n-type 3D TIs Bi 2 Te 3 combined with p-type pentacene thin film was designed and fabricated. Surprisingly, it was found that the Bi 2 Te 3 /pentacene heterojunction photodetector exhibited a fast and wideband response from 450 to 3500 nm. The optimized responsivity of photodetector reached 14.89 A/W, along with the fast response time of 1.89 ms and the ultrahigh external quantum efficiency of 2840%. Moreover, at the mid-IR 3500 nm, our devices demonstrated a responsivity of 1.55 AW −1 , which was several orders of magnitude higher than that of previous 3D TIs photodetector. These excellent properties indicate that the inorganic/organic heterojunction, that is, the combination of 3D TIs with organic materials, is an exciting structure for high performance photodetectors in the wideband detection region. On account of the fact that the device is constructed on mica substrate, this work also represents a potential scenario for flexible optoelectronic devices. KEYWORDS: inorganic/organic heterojunction, wideband photodetector, Bi 2 Te 3 thin films, self-powered, fast response, flexible

Ultrahigh Stability 3D TI Bi2Se3/MoO3 Thin Film Heterojunction Infrared Photodetector at Optical Communication Waveband

“…The maximum on–off ratio of this device is 5.32 × 10 4 @ 650 nm, which is more than two orders of magnitude higher than similar devices previously reported ( Table 1 ). Therefore, the device has more distinguished I – V rectification characteristics than other reported devices based on TIs materials. In Bi 2 Se 3 /MoO 3 heterojunction, the Fermi energy level ( E f ) of N‐type material Bi 2 Se 3 is −5.3 eV and the bandgap is 0.3 eV.…”

“…By measuring the response time of the device, the optical response performance is deeply studied. Impressively, the response time reached a staggering 62 µs, better than many previously reported IR devices at room temperature . The heterogeneous structure based on Bi 2 Se 3 has great application potential in the field of photoelectric detection, which provides a feasible direction for the application of 3D TIs materials.…”

“…The response time of the device was measured by an independently built test platform (Figure S11, Supporting Information), which included current amplifier (SR570), digital source meter, oscilloscope (InfiniiVision DXO‐X 2024A), signal source (Rigol DG1022U), direct current power source (Rigol DP821), test computer, and lasers. In addition, 10–90% of the rise and fall time process was defined as the τ on and τ off of the device …”

“…Lately, Das et al prepared Bi 2 Se 3 /Si nanowire heterojunction photodetector, which had a 932 A W −1 responsivity ( R i ) with a response time of about 41 ms at NIR region . Yang et al fabricated 3D TIs/organic thin film heterojunction devices, whose R i and response time reached 14.89 A W −1 and 1.89 ms at 650 nm . Nevertheless, the above TIs‐based photodetectors still have space for improvement at optical communication waveband.…”

Enhancement of Charge Transport in Polythiophene Semiconducting Polymer by Blending with Graphene Nanoparticles

“…Such tunability will enable new functionalities in future electronic devices. Besides graphene, the phenomena of high light sensitivity were also found in other combinations of organic semiconductors and two‐dimensional materials . These applications call into question the phenomena of charge transport in OSP‐graphene blends.…”