Abstract
Two-dimensional (2D) Ruddlesden-Popper perovskites are currently drawing significant attention as highly-stable photoactive materials for optoelectronic applications. However, the insulating nature of organic ammonium layers in 2D perovskites results in poor charge transport and limited performance. Here, we demonstrate that Al2O3/2D perovskite heterostructure can be utilized as photoactive dielectric for high-performance MoS2 phototransistors. The type-II band alignment in 2D perovskites facilitates effective spatial separation of photo-generated carriers, thus achieving ultrahigh photoresponsivity of >108 A/W at 457 nm and >106 A/W at 1064 nm. Meanwhile, the hysteresis loops induced by ionic migration in perovskite and charge trapping in Al2O3 can neutralize with each other, leading to low-voltage phototransistors with negligible hysteresis and improved bias stress stability. More importantly, the recombination of photo-generated carriers in 2D perovskites depends on the external biasing field. With an appropriate gate bias, the devices exhibit wavelength-dependent constant photoresponsivity of 103–108 A/W regardless of incident light intensity.
Highlights
Two-dimensional (2D) Ruddlesden-Popper perovskites are currently drawing significant attention as highly-stable photoactive materials for optoelectronic applications
Cr/Au (15/50 nm) electrodes were patterned on MoS2 flakes using e-beam lithography (EBL) and metal thermal evaporation
After atomic layer deposition (ALD) of 9 nm Al2O3, 2D perovskite (PEA)2(MA)n−1PbnI3n+1 was deposited by the one-step spin coating method
Summary
Two-dimensional (2D) Ruddlesden-Popper perovskites are currently drawing significant attention as highly-stable photoactive materials for optoelectronic applications. Owing to the external biasing field-dependent photo-generated carriers recombination in 2D perovskite, the device exhibits a constant responsivity of 2.4 × 105 A/W, a corresponding specific detectivity of 5.5 × 1012 Jones, and a large linear dynamic range (LDR) of 45 dB upon 914 nm illumination, suggesting an excellent linear dynamic characteristic. To clearly verify the improvement of this heterostructure dielectric for highly sensitive photodetection, the photodetectors based on bare MoS2, MoS2/ Al2O3, and MoS2/Al2O3/2D perovskite (n = 3) with the same MoS2 flake are fabricated and characterized under the same measurement conditions (e.g., laser power density of Plight = 1232.2 μW/cm[2], wavelength of λ = 914 nm, and gate voltage of Vgs = 0 V).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
