Periodic Reporting for period 1 - Multi GRAPH (Investigation of Disruptive 2D/Silicon Technology for Hybrid Multispectral Photodetection)
Okres sprawozdawczy: 2022-10-01 do 2025-03-31
Light detection is a fundamental process lying in the foundation of optoelectronics. The research and application of photodetectors promote the progress and development of our society. The role of photodetectors is to convert radiant energy into electrical output signals, current or voltage. Modern solid-state PDs rely on a range of materials and/or technologies such as Si (0.3-1.1µm wavelengths range), Ge (0.5-1.8µm), InGaAs (0.7-1.7µm), narrow-gap semiconductors InSb (2-6µm), PbS (1-3.6µm), PbSe (1.5-5.8 µm) and HgCdTe (2-16µm), each of them optimized for a specific spectral range with a limited prospect for integration between different platforms. The operation principle of solid-state (semiconductor, SC) PDs is governed by the photoelectric effect, where optical absorption of quanta of light (i.e. a photon) generates free carriers (FCs), electrons and holes via band-to-band (or defect-assisted) transition over the energy bandgap or sub-bandgap potential barrier. The FCs can drift in the electric field and/or diffuse along a temperature (or concentration) gradient to produce a photovoltage response across the output terminals or photocurrent flow in an external circuit.
An extreme diversity of modern multi- and hyperspectral imaging applications, ranging from remote healthcare and environmental monitoring, gas sensing and hazard detection, food and water inspection to biosensing and automotive, share similar urgent needs for high-performance, miniaturized, and lightweight multispectral optical sensors monolithically integrated with low-cost and high-functionality silicon electronics. However, current semiconductor PDs technologies are mainly tailored and optimized to specific spectral bands, and their roadmaps have so far prevented the development of a universal solution for multispectral detectors that could simultaneously address broadband operation spanning from visible to mid-infrared wavelengths. Quite the opposite, different PDs technologies have become so specialized for their band of operation that no viable avenue exists to integrate current state-of-the-art solutions. Thus, there is a pressing need for a radically new approach that could combine high-performance broadband PDs for all spectral bands in one single silicon-based technological platform. Graphene and 2D materials integration with silicon technology opens an unprecedented opportunity to reach this goal, leveraging unique ultra-broadband absorption properties of graphene and the diversity of the 2D family with mature silicon fabrication facilities for scalable and cost-effective monolithic integration with modern read-out electronics and integrated circuits. The project's grand challenge is to radically expand the photodetection capabilities of silicon technology far beyond the visible (VIS) spectrum covering multiple spectral bands, including the infrared (IR), with an ultimate goal of demonstrating that 2D/Silicon integration can represent the long-sought one single technology for a multispectral photodetection at room-temperature outperforming the state-of-the-art solutions.
The proposed research's ultimate goal is to develop novel approaches for multispectral optical detection in emerging 2D hybrid-silicon technology and unify high-performance photodetectors operating in all spectral bands from visible to mid-infrared in one single technological platform. To tackle this highly multidisciplinary research program, the project proposes theoretical and experimental studies of new concepts and physical phenomena for multispectral photodetection in integrated 2D/Silicon hybrids, aiming for innovative solutions, novel device architectures, and disruptive technological development of silicon-based multi- and hyperspectral photodetection systems-on-chip.
An extreme diversity of modern multi- and hyperspectral imaging applications, ranging from remote healthcare and environmental monitoring, gas sensing and hazard detection, food and water inspection to biosensing and automotive, share similar urgent needs for high-performance, miniaturized, and lightweight multispectral optical sensors monolithically integrated with low-cost and high-functionality silicon electronics. However, current semiconductor PDs technologies are mainly tailored and optimized to specific spectral bands, and their roadmaps have so far prevented the development of a universal solution for multispectral detectors that could simultaneously address broadband operation spanning from visible to mid-infrared wavelengths. Quite the opposite, different PDs technologies have become so specialized for their band of operation that no viable avenue exists to integrate current state-of-the-art solutions. Thus, there is a pressing need for a radically new approach that could combine high-performance broadband PDs for all spectral bands in one single silicon-based technological platform. Graphene and 2D materials integration with silicon technology opens an unprecedented opportunity to reach this goal, leveraging unique ultra-broadband absorption properties of graphene and the diversity of the 2D family with mature silicon fabrication facilities for scalable and cost-effective monolithic integration with modern read-out electronics and integrated circuits. The project's grand challenge is to radically expand the photodetection capabilities of silicon technology far beyond the visible (VIS) spectrum covering multiple spectral bands, including the infrared (IR), with an ultimate goal of demonstrating that 2D/Silicon integration can represent the long-sought one single technology for a multispectral photodetection at room-temperature outperforming the state-of-the-art solutions.
The proposed research's ultimate goal is to develop novel approaches for multispectral optical detection in emerging 2D hybrid-silicon technology and unify high-performance photodetectors operating in all spectral bands from visible to mid-infrared in one single technological platform. To tackle this highly multidisciplinary research program, the project proposes theoretical and experimental studies of new concepts and physical phenomena for multispectral photodetection in integrated 2D/Silicon hybrids, aiming for innovative solutions, novel device architectures, and disruptive technological development of silicon-based multi- and hyperspectral photodetection systems-on-chip.
During the first two years of the project, we have progressed in all work packages, achieved the relevant milestones, and established a solid basis for successfully accomplishing the project goals. The major developments and achievements per work package are presented in the following section:
2D/Silicon Broadband PDs
1) We performed theoretical investigations and developed simulation modules for ion implantation and thermal diffusion processes of non-standard species (e.g. S, Se , Te) in Si. We developed numerical simulations and investigated different photo-thermionic PDs configurations.
2) We performed implantation tests of various species into Si and characterized the associated defect states created within the Si bandgap. We studied different annealing techniques, including thermal furnaces, rapid-thermal annealing, and flash-lamp annealing, to activate and enhance the light-defect cross-section of interaction. We implanted numerous samples and studied and optimized Graphene- and TMD/Si interfaces.
3) We developed advanced 2D/Si PDs configurations to enhance photoresponse and demonstrated defect-assisted G/Si Schottky PDs at different wavelengths corresponding to specific defect states.
4) Development and realization of TMD-based self-powered PD operating at SWIR based on combined photo-thermoelectric and internal photoemission effects. The realized devices demonstrated voltage responsivity beyond the state-of-the-art.
Multispectral super-sensor
1) We developed and optimized the fabrication processes for defect-assisted and thermionic hybrid 2D PDs, including the graphene transfer, ion-implantation, lithography, and metalization. We also optimized the graphene and TMD-Si interfaces for efficient charge transfer. As part of the material characterization, we established spectroscopic, microscopic, optical absorption and electrical measurements and corresponding setups.
2) We started the investigation of multi-level defects-assisted super-sensor based on a single PD configuration, including the study of multispectral absorption in vdW heterostructures using exfoliated 2D materials.
Integrated System
1) We designed the semi-automatic transfer system and upscaled and optimized the vacuum-assisted transfer process of 2D materials to wafer-scale. We optimized the large-area graphene transfer using the designed system. We developed an advanced encapsulation of graphene and silicon using 2D materials and semi-automatic transfer setup.
2) We optimized the process flow for wafer-scale fabrication of multispectral super-sensors. We develop a direct transfer method of large-area CVD-grown 2D materials vdW heterostructures using a semi-automatic transfer system.
2D/Silicon Broadband PDs
1) We performed theoretical investigations and developed simulation modules for ion implantation and thermal diffusion processes of non-standard species (e.g. S, Se , Te) in Si. We developed numerical simulations and investigated different photo-thermionic PDs configurations.
2) We performed implantation tests of various species into Si and characterized the associated defect states created within the Si bandgap. We studied different annealing techniques, including thermal furnaces, rapid-thermal annealing, and flash-lamp annealing, to activate and enhance the light-defect cross-section of interaction. We implanted numerous samples and studied and optimized Graphene- and TMD/Si interfaces.
3) We developed advanced 2D/Si PDs configurations to enhance photoresponse and demonstrated defect-assisted G/Si Schottky PDs at different wavelengths corresponding to specific defect states.
4) Development and realization of TMD-based self-powered PD operating at SWIR based on combined photo-thermoelectric and internal photoemission effects. The realized devices demonstrated voltage responsivity beyond the state-of-the-art.
Multispectral super-sensor
1) We developed and optimized the fabrication processes for defect-assisted and thermionic hybrid 2D PDs, including the graphene transfer, ion-implantation, lithography, and metalization. We also optimized the graphene and TMD-Si interfaces for efficient charge transfer. As part of the material characterization, we established spectroscopic, microscopic, optical absorption and electrical measurements and corresponding setups.
2) We started the investigation of multi-level defects-assisted super-sensor based on a single PD configuration, including the study of multispectral absorption in vdW heterostructures using exfoliated 2D materials.
Integrated System
1) We designed the semi-automatic transfer system and upscaled and optimized the vacuum-assisted transfer process of 2D materials to wafer-scale. We optimized the large-area graphene transfer using the designed system. We developed an advanced encapsulation of graphene and silicon using 2D materials and semi-automatic transfer setup.
2) We optimized the process flow for wafer-scale fabrication of multispectral super-sensors. We develop a direct transfer method of large-area CVD-grown 2D materials vdW heterostructures using a semi-automatic transfer system.
1) Development and realization of TMD-based self-powered PD. The device responsivity is 180 V/W, the highest reported in the literature for self-powered PD. Further optimization of the vdW contacts bottleneck with efficient heat flow is necessary to enhance the performance. Additional research on 2D semiconductors with increased thermoelectric properties is required to improve TMD thermal detectors.
2) Development and realization of a direct large-area transfer of vdW heterostructures. Further process optimization is required to improve the uniformity and increase the number of layers of the vdW stack.
2) Development and realization of a direct large-area transfer of vdW heterostructures. Further process optimization is required to improve the uniformity and increase the number of layers of the vdW stack.