Researchers at AMO, Graphenea Semiconductor and Emberion recently demonstrated a 200 mm processing platform for the large-scale production of graphene field-effect transistor-quantum dot (GFET-QD) hybrid photodetectors. Such sensors have many potential applications, ranging from surveillance, search and rescue, and vehicle safety to improved sorting of food and food packaging to reduce their environmental impact.
Schematic of the device architecture of the tandem GFET‒QD photodetector. Image from: Scientific Reports
The team addressed several of the graphene wafer-scale integration challenges, including monolayer graphene chemical vapor deposition (CVD), transfer, and patterning, which fulfill the requirements for imaging functionalization and large area deposition of the multilayer QD absorber material in an inert atmosphere, as well as methods for encapsulating devices using thin film alumina (Al2O3) and hermetically sealed semiconductor packages. Such a demonstration elevates the initial concept to higher technology readiness levels in multiple dimensions, ranging from wafer-scale graphene device statistics to the development of custom CMOS circuits and the implementation of production-ready packaging.
A comprehensive statistical analysis of the electrical data reportedly showed a high yield (96%) and low variation in the 200 mm scale fabrication. The GFET-QD devices deliver responsivities of 105 to 106 V/W in the wavelength range from 400 to 1800 nm with a response time of 10 ms. The spectral sensitivity compares well to that obtained via similar GFET-QD photodetectors.
The device concept enables gate-tunable suppression or enhancement of the photovoltage, which may be exploited for electric shutter operation by toggling between the signal capture and shutter states.
The devices show good stability over a wide operation range. Furthermore, an integration solution with complementary metal-oxide-semiconductor technology is presented to realize image-sensor-array chips and a proof-of-concept image system.
This work demonstrates the potential for the volume manufacture of infrared photodetectors for a wide range of imaging applications.
