Air processed Cs2AgBiBr6 lead-free double perovskite high-mobility thin-film field-effect transistors

Gnanasampanthan Abiram,Thanihaichelvan Murugathas,Selvakumar Pitchaiya,Dhayalan Velauthapillai,Fatemeh Heidari Gourji,Punniamoorthy Ravirajan

doi:10.1038/s41598-022-06319-z

Gnanasampanthan Abiram, Thanihaichelvan Murugathas + Show 4 more

Open Access

https://doi.org/10.1038/s41598-022-06319-z

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Abstract

This study focuses on the fabrication and characterization of Cs2AgBiBr6 double perovskite thin film for field-effect transistor (FET) applications. The Cs2AgBiBr6 thin films were fabricated using a solution process technique and the observed XRD patterns demonstrate no diffraction peaks of secondary phases, which confirm the phase-pure crystalline nature. The average grain sizes of the spin-deposited film were also calculated by analysing the statistics of grain size in the SEM image and was found to be around 412 (± 44) nm, and larger grain size was also confirmed by the XRD measurements. FETs with different channel lengths of Cs2AgBiBr6 thin films were fabricated, under ambient conditions, on heavily doped p-type Si substrate with a 300 nm thermally grown SiO2 dielectric. The fabricated Cs2AgBiBr6 FETs showed a p-type nature with a positive threshold voltage. The on-current, threshold voltage and hole-mobility of the FETs decreased with increasing channel length. A high average hole mobility of 0.29 cm2 s−1 V−1 was obtained for the FETs with a channel length of 30 µm, and the hole-mobility was reduced by an order of magnitude (0.012 cm2 s−1 V−1) when the channel length was doubled. The on-current and hole-mobility of Cs2AgBiBr6 FETs followed a power fit, which confirmed the dominance of channel length in electrostatic gating in Cs2AgBiBr6 FETs. A very high-hole mobility observed in FET could be attributed to the much larger grain size of the Cs2AgBiBr6 film made in this work.

Highlights

This study focuses on the fabrication and characterization of Cs2AgBiBr6 double perovskite thin film for field-effect transistor (FET) applications
This study focuses on investigating the structural phase purity and morphological formation of solutionprocessed Cs2AgBiBr6 double perovskite thin films. Cs2AgBiBr6 double perovskite has primarily been studied for solar cells a pplications[21] until recent study on its application for FET by Li et al.22 Cs2AgBiBr6 double Perovskite thin-film has been served as channel which is studied based on the existence of grains and grain boundaries of interlayers[17,22]
From the observed XRD results, all the obtained major peaks located at 13.63°, 15.73°, 22.34°, 27.41°, 31.77°, 35.56°, 39.23°, 45.56°, and 56.53° attribute to the reflections of C s2AgBiBr6 having the plane values of (002), (200), (220), (222), (400), (331), (224), (044), and (444), all the peaks correlate with the standard JCPDS (File number: 01-084-8699) data and are in good agreement with the previous reports on double perovskite Cs2AgBiBr6 materials[25–27]

Summary

Introduction

This study focuses on the fabrication and characterization of Cs2AgBiBr6 double perovskite thin film for field-effect transistor (FET) applications. The on-current and hole-mobility of Cs2AgBiBr6 FETs followed a power fit, which confirmed the dominance of channel length in electrostatic gating in Cs2AgBiBr6 FETs. A very high-hole mobility observed in FET could be attributed to the much larger grain size of the Cs2AgBiBr6 film made in this work. Despite the eco-friendliness and long-term stability C s2AgBiBr6 possess, the large indirect bandgap and poor light absorption ability of the material have restricted their applicability in solar cell technologies. 1 μm and long-term environmental stability than organic–inorganic lead-halide perovskites, make it a promising material for a wide range of applications such as light-emitting diodes (LEDs), radiation detectors, photodetectors, photocatalysts, sensors and in neuromorphic c omputing[17–20]. We conclude that the enhanced mobility could be attributed to the larger grain size and high-quality thin film produced by recrystallization of C s2AgBiBr6 crystals during the thin film deposition

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