Istituto di Cristallografia - CNR

Single crystal perovskite nanopixel arrays for miniaturized image sensors

Moore’s law trajectory continues to inspire device downscaling in semiconductor science and technology. Next in line for
miniaturization are integrated nanoscale optoelectronic devices able to interface electronics with light. Particular efforts are devoted
to miniaturizing image sensors: smaller pixels improve resolution and at the same time reduce the distance between the lenses and
the image sensor, making the whole camera not only smaller in footprint but also thinner. In the past 20 years, pixel size has been
reduced from around 1.2 micron down to 0.64 micron in 2021, with the Samsung JN1 Isocell sensor packing 50 Mpixels within a
surface area around 20 mm2, and reportedly down to 0.56 micron in 2022, as announced by Samsung and Omnivision. Further pixel
miniaturization may not only improve existing architectures, but also allow innovative quantum technologies such as sub-diffraction
and polarization-sensitive imaging. Significant progress however needs suitable materials that can be easily nanostructured,
integrated into semiconductor processing and simultaneously able to transform electrical current into light of the desired colour and
vice versa with high efficiency and large frequency bandwidth.
Metal halide perovskites have been demonstrated as very promising materials for solar cells, photodetectors and LEDs, with almost
unit efficiency in converting light into electric current and easy solution-processing.1–6 We posit that such features combined with
the ability to precisely control the growth of perovskite materials will offer opportunities for image sensor miniaturization.
Specifically, NanoPix targets the demonstration of perovskite single crystal (PVSK-SC) nanopixel arrays. The realization will exploit
the synergy of the complementary know-how of the consortium members in the research field of materials preparation,
characterization, device fabrication and optoelectronics. Perovskite synthesis in NanoPix will pioneer an innovative synthetic
approach based on a capillary bridge to confine crystallization into nano-space with precise geometry and antisolvent vapour
assisted growth methods to drive and control nucleation and crystal growth. The resulting perovskite single crystals with controlled
morphology, alignment, orientation and crystallographic quality will represent the core building blocks for nanopixels. The flexibility
in the selection of precursors and antisolvents based on their physicochemical properties will realize a general method suitable for
perovskites with different composition and dimensionalities. In addition, we will demonstrate that this method is compatible with
device integration by fabricating a PVSK-SC nanopixel array on substrates with pre-patterned electrodes. As a proof of concept, we
will also demonstrate the imaging capabilities of the image sensor based on PVSK-SC nanopixel arrays.

Bando / Avviso
PRIN 2022
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Responsabile IC CNR
Altro personale IC CNR