Defect-Assisted High Photoconductive UV–Visible Gain in Perovskite-Decorated Graphene Transistors

Nathan D Cottam,Oleg Makarovsky,Evgenii E Vdovin,Laurence Eaves,Chengxi Zhang,Amalia Patanè,Zakhar Kudrynskyi,Lyudmila Turyanska

doi:10.1021/acsaelm.9b00664

Nathan D Cottam, Oleg Makarovsky + Show 6 more

Open Access

https://doi.org/10.1021/acsaelm.9b00664

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Abstract

Recent progress in the synthesis of high stability inorganic perovskite nanocrystals (NCs) has led to their increasing use in broadband photodetectors. These NCs are of particular interest for the UV range as they have the potential to extend the wavelength range of photodetectors based on traditional materials. Here we demonstrate a defect-assisted high photoconductive gain in graphene transistors decorated with all-inorganic caesium lead halide perovskite NCs. The photoconductive gain in the UV-VIS wavelength range arises from the charge transfer between the NCs and graphene and enable observation of high photoconductive gain of 106 A/W. This is accompanied by a giant hysteresis of the graphene resistance that is strongly dependent on electrostatic gating and temperature. Our data are well described by a phenomenological macroscopic model of the charge transfer from bound states in the NCs into the graphene layer, providing a useful tool for the design of high-photoresponsivity perovskite/graphene trans...

Highlights

Rapid progress in semiconductor science and technology has led to the development of novel device concepts which combine two-dimensional (2D) van der Waals crystals, such as graphene, with an adjacent layer of an optically active 0D, 2D, or 3D material.[1−4] For example, a record high photoresponsivity (R > 109 A/W) has been achieved by depositing photoresponsive 0D nanocrystals (NCs) of II−VI or IV−VI QDs (CdSe, CdS, PbS, etc.) on the surface of single layer graphene (SLG).[4−6] These hybrid structures are of particular interest for near-infrared (NIR) graphene-based complementary metal-oxide-semiconductor (CMOS) image sensors.[7]
Cesium lead halide perovskite nanocrystals were synthesized following the method reported in ref 16 and were capped with a mixture of oleic acid (OA), oleylamine (OLA), and iminodiacetic acid (IDA) (Figure 1a)
We propose that the shorter ligands used in our NCs (IDA replacement) enable more efficient charge transfer between the NC layer and the SLG, and shorter response times

Summary

Introduction

Rapid progress in semiconductor science and technology has led to the development of novel device concepts which combine two-dimensional (2D) van der Waals (vdW) crystals, such as graphene, with an adjacent layer of an optically active 0D, 2D, or 3D material.[1−4] For example, a record high photoresponsivity (R > 109 A/W) has been achieved by depositing photoresponsive 0D nanocrystals (NCs) of II−VI or IV−VI QDs (CdSe, CdS, PbS, etc.) on the surface of single layer graphene (SLG).[4−6] These hybrid structures are of particular interest for near-infrared (NIR) graphene-based complementary metal-oxide-semiconductor (CMOS) image sensors.[7] More recently, organic[8] and inorganic[9] perovskite nanocrystals with high optical quantum yield have been used in combination with graphene[10−13] to achieve photoresponsivity of up to 109 A/W and detectivity of 109 Jones. Despite a growing number of experimental reports on the application of perovskite NC/graphene in optoelectronic devices,[8−10] one of the key challenges is understanding and controlling the charge transfer at the interface of these heterostructures.[15]

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