Abstract:
This study focuses on the fabrication and characterization of Cs2AgBiBr6 double perovskite thin flm
for feld-efect transistor (FET) applications. The Cs2AgBiBr6 thin flms were fabricated using a solution
process technique and the observed XRD patterns demonstrate no difraction peaks of secondary
phases, which confrm the phase-pure crystalline nature. The average grain sizes of the spin-deposited
flm 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 confrmed by the XRD measurements. FETs
with diferent channel lengths of Cs2AgBiBr6 thin flms 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 ft, which confrmed
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 flm made in this
work.
