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

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.

Two-Dimensional Cs2AgBiBr6-Based Biosensor for Selective and Sensitive Detection of Cardiac Biomarker Troponin I

“…The slopes of the linearly fitted lines for the I – V curves before and after the functionalization of cTnI antibody-conjugated yolk–shell nanomaterials are 0.0198 and 0.0249 pA/V, respectively. This increment in current can be attributed to the p-doping effect of the yolk–shell nanomaterials and the p-type nature of Cs 2 AgBiBr 6 . ,, To probe their sensing capability, the 2D Cs 2 AgBiBr 6 -based biosensors were exposed to cTnI at various concentrations from 0 to 10 000 pg/mL in Tris-buffered saline (pH 7.4). The isoelectric point (pI) of cTnI protein is around 5; therefore, the surface charge of cTnI is negative under the physiological condition of pH 7.4. , The I – V characteristics obtained from the cTnI-exposed 2D Cs 2 AgBiBr 6 biosensor revealed a notable increase in the slope of the I – V curve, approximately 26 times increase upon exposure to cTnI at a concentration of 10 000 pg/mL (Figure c).…”

“…This increment in current can be attributed to the p-doping effect of the yolk−shell nanomaterials and the p-type nature of Cs 2 AgBiBr 6 . 31,35,36 To probe their sensing capability, the 2D Cs 2 AgBiBr 6 -based biosensors were exposed to cTnI at various concentrations from 0 to 10 000 pg/mL in Tris-buffered saline (pH 7.4). The isoelectric point (pI) of cTnI protein is around 5; therefore, the surface charge of cTnI is negative under the physiological condition of pH 7.4.…”

Review on Perovskite Semiconductor Field–Effect Transistors and Their Applications

“…The Cs 2 AgBiBr 6 thin-film FETs were studied, and the dominance of the grain boundaries in gating and conduction has been reported. The hole mobility values of Cs 2 AgBiBr 6 thin-film FETs were shown to strongly depend on the grain boundaries [ 147 , 148 ]. The FET literatures based on the double and triple perovskites and their features after 2012 are summarized in Table 4 .…”

Transformation of Polarization Mechanisms by Dimensional Reduction in Lead-Free Silver Bismuth Bromide Double-Perovskite Thin Films

“…42 Also, field-effect transistors (FETs) have been realized. 43,44 Cs 2 AgBiBr 6 exhibits intrinsic p-type conductivity, arising from shallow acceptor states caused by Ag vacancies. 1 Moreover, Bi-vacancies and Ag-Bi-antisites would lead to undesired deep acceptors, which could be avoided by appropriate conditions during film growth.…”