Wafer-Scale 1T' MoTe2 for Fast Response Self-Powered Wide-Range Photodetectors.

Abstract

The semimetal-based photodetector possesses the intrinsic advantage of high response speed, low power consumption, and wide-range photoresponse. Here, we report the synthesis and application of 1 inch wafer-scale polycrystalline few layer 1T'-MoTe2 on the SiO2/Si substrate by employing a modified chemical vapor deposition method of predeposition of precursors. A continuous film with seamlessly stitched micrometer scale grains has been realized, and the pure 1T' phase was confirmed by Raman spectroscopy. An asymmetric metal electrode photodetector device of Pd-MoTe2-Au was designed and fabricated by using shadow mask-assisted UHV deposition. By measuring the self-powered photocurrent under the illumination of Xe lamp, we show that the device is sensitive to a wide spectra range (λ = 320-1200 nm) while maintaining high performance of the ON/OFF ratio (∼103), responsivity (1.2 A/W), and specific detectivity (7.68 × 1012 Jones). Under 450, 648, and 850 nm pulsed laser illumination, the response time achieves tens of microsecond scale. The device shows polarized photoresponse as well. Our work may promote the potential application of a self-powered high-performance photodetector based on 1T'-MoTe2.