Graphene, quantum dots integrated in CMOS sensor

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Graphene Flagship researchers have integrated graphene, quantum dots and CMOS technology to create an array of photodetectors which is being used in a high resolution image sensor. When used as a digital camera, the device can sense UV, visible and infrared light at the same time. Other applications include microelectronics, sensor arrays and low-power photonics.

“The development of this monolithic CMOS-based image sensor represents a milestone for low-cost, high-resolution broadband and hyperspectral imaging systems,” said Professor Frank Koppens from Spanish research centre ICFO. “In general, graphene-CMOS technology will enable a vast amount of applications, ranging from safety, security and fire control systems [to] automotive sensor systems and medical imaging.”

By creating a hybrid graphene and quantum dot system on a CMOS wafer using a layering and patterning approach, the Flagship team said a complex problem had been solved simply. In the method, graphene is deposited, then patterned to define the pixel shape, after which a layer of PbS colloidal quantum dots is added. The photo signal is sensed by the change in conductivity of the graphene, with graphene’s high charge mobility allowing for the high sensitivity of the device.

Professor Andrea Ferrari, chair of the Graphene Flagship’s management panel, added: “The integration of graphene with CMOS technology is a cornerstone for the future implementation of graphene in consumer electronics. This work is a key first step, clearly demonstrating the feasibility of this approach. The Flagship has put a significant investment in the system level integration of graphene and this will increase as we move along the technology and innovation roadmap.”