Near‐Infrared Electroluminescent Light‐Emitting Transistors Based on CVD‐Synthesized Ambipolar ReSe2 Nanosheets

• Published in: Advanced optical materials 2022-04, Vol.10 (8), p.n/a
• Main Authors: Mathew, Roshan Jesus, Cheng, Kai‐Hsiang, Hsu, Ching‐Hong, Chand, Pradyumna Kumar, Paul Inbaraj, Christy Roshini, Peng, Yu‐Lou, Yang, Jung‐Yen, Lee, Chih‐Hao, Chen, Yit‐Tsong
• Format: Article
• Language: English
• Subjects: ambipolar electrical transport; Bandpass filters; Chemical synthesis; Chemical vapor deposition; Chromium; Conduction bands; Crystal structure; Data communication; Electric potential; Electroluminescence; light‐emitting transistors; Materials science; Medical imaging; Nanosheets; Near infrared radiation; near‐infrared electroluminescence; Optics; ReSe 2 2D crystal; Semiconductor devices; Temperature dependence; Transistors; Two dimensional materials; Voltage; Work functions
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202102580

Near‐infrared light‐emitting technology is ideal for noncontact diagnostic medical imaging and high‐speed data communications. High‐quality ReSe2 nanosheets of anisotropic single‐crystal structure with a bandgap of 1.26 eV (≈984 nm) are synthesized with an atmospheric pressure chemical vapor deposition (APCVD) method. The as‐synthesized ReSe2 nanosheets‐fabricated light‐emitting transistors (LETs) exhibit nearly symmetric ambipolar characteristics in electrical transport. Judicious selection of asymmetric platinum (Pt)/chromium (Cr) electrodes, with their work functions matching respectively the conduction‐ and valence‐band edges of ambipolar ReSe2, generates a low turn‐on voltage ReSe2‐LET with the balanced number density and field‐effect mobility of bipolar carriers (i.e., electrons and holes). Room‐temperature near‐infrared electroluminescence (NIR EL) from the frequency‐modulated ReSe2‐LET has been observed unprecedentedly with the assistance of a lock‐in detection system. The NIR EL intensity is tested by varying the bias voltage applied to the ReSe2‐LET devices with different channel lengths. The wavelength of the NIR EL from ReSe2‐LET is differentiated with optical bandpass filters. Room‐temperature angle‐dependent two lobe‐shaped EL pattern manifests the inherent anisotropic in‐plane excitonic polarization of the ReSe2 crystal. The highly stable NIR EL from ReSe2‐LETs provides prospective 2D material‐based ultrathin scalable data communication electronics for future development. Single‐crystalline ReSe2 nanosheets with nearly symmetric ambipolar electrical transports are used as a conducting channel to fabricate light‐emitting transistors (LETs) by connecting a pair of asymmetric Pt/Cr electrodes. The ReSe2‐LETs, holding the balanced number density and field‐effect mobility of bipolar carriers, can be driven by low turn‐on voltage. Room‐temperature near‐infrared electroluminescence from the ReSe2‐LET has been observed unprecedentedly.