Periodic Reporting for period 1 - Next-2Digits (The next generation of sensors and imagers enabled by 2D materials digital integration)
Reporting period: 2023-10-01 to 2025-03-31
Next-2Digits is driving forward the integration of graphene and other 2D materials into PICs and OEICs to improve performance, compactness, and cost-efficiency. By enabling direct wafer-scale integration of graphene, the project aims to reduce impurities and defects, using two advanced transfer techniques:
1. Semi-dry transfer for both wafer-scale and direct die processing.
2. Laser Digital Transfer (LDT) for precise, single-step placement and patterning of 2DM pixels.
These approaches offer clear benefits, such as cleaner interfaces and fewer defects, which in turn enhance electronic mobility and bandwidth. Additionally, they contribute to lower costs, reduced material and energy usage, and minimized waste.
Next-2Digits will demonstrate its graphene integration technologies in three main application areas:
1. LiDAR for drones: Graphene photodetectors support compact, high-resolution geo-mapping with a significantly reduced system footprint.
2. Greenhouse gas sensors: A multi-sensor PIC for biogas plants enables real-time, cost-effective monitoring and leak detection, integrated into IoT networks.
3. Polarization Diversity Receivers (PDRs): Designed for biomedical imaging via Optical Coherence Tomography (OCT), these graphene-enhanced PICs offer improved resolution and bandwidth compared to conventional bulk optics.
Addressing Technical Challenges
• LiDAR: Tackles the need for small detector footprints with a compact 10x10 mm² array that delivers sub-0.1 mm resolution and supports high-speed detection (500 GHz), while meeting requirements for range and lightweight design.
• Gas sensors: Utilizes graphene’s capabilities in mid-infrared emission and detection to enable NDIR sensing with detection limits around 50 ppm.
• PDRs: Replaces bulky optics with miniaturized graphene PICs that can detect multiple polarizations, simplifying assembly by reducing alignment steps and accelerating production.
1. Semi-dry transfer for both wafer-scale and direct die processing.
2. Laser Digital Transfer (LDT) for precise, single-step placement and patterning of 2DM pixels.
These approaches offer clear benefits, such as cleaner interfaces and fewer defects, which in turn enhance electronic mobility and bandwidth. Additionally, they contribute to lower costs, reduced material and energy usage, and minimized waste.
Next-2Digits will demonstrate its graphene integration technologies in three main application areas:
1. LiDAR for drones: Graphene photodetectors support compact, high-resolution geo-mapping with a significantly reduced system footprint.
2. Greenhouse gas sensors: A multi-sensor PIC for biogas plants enables real-time, cost-effective monitoring and leak detection, integrated into IoT networks.
3. Polarization Diversity Receivers (PDRs): Designed for biomedical imaging via Optical Coherence Tomography (OCT), these graphene-enhanced PICs offer improved resolution and bandwidth compared to conventional bulk optics.
Addressing Technical Challenges
• LiDAR: Tackles the need for small detector footprints with a compact 10x10 mm² array that delivers sub-0.1 mm resolution and supports high-speed detection (500 GHz), while meeting requirements for range and lightweight design.
• Gas sensors: Utilizes graphene’s capabilities in mid-infrared emission and detection to enable NDIR sensing with detection limits around 50 ppm.
• PDRs: Replaces bulky optics with miniaturized graphene PICs that can detect multiple polarizations, simplifying assembly by reducing alignment steps and accelerating production.
To advance its objectives, Next-2Digits structured its work into five technical Work Packages (WPs).
WP1 – Requirements and Specifications:
The project reviewed existing system specs and proposed enhanced ones tailored to the needs of each application, prioritising factors like size for LIDAR, response time for greenhouse gas sensing, and spectral response for OCT. Tailored requirements for the three demonstrators were successfully defined, along with PIC design choices.
WP2 – 2D Materials Growth and Platform Development:
GSEMI supplied various graphene donor substrates to NTUA, which conducted DFT-based quantum-mechanical simulations to study graphene behaviour on receiver substrates and detachment processes from metallic donors. VTT optimised optical mode simulations for detector integration. First-generation 2D material and SOI platform qualification tests were completed, and initial wafer processing for graphene integration was successfully conducted by SILEX and VTT.
WP3 – 2D Material Digital Transfer and Integration:
NTUA began developing a laser direct transfer (LDT) station to meet graphene photodetector needs. The LIFT method was demonstrated as a fast, low-cost way to integrate 2D materials onto chips. Arrays of graphene pixels were successfully transferred and integrated into photodetector prototypes, now under evaluation by VTT. Material integrity was validated using advanced microscopy and spectroscopy techniques. GSEMI also achieved semi-dry monolayer graphene transfers on multiple 8-inch wafers from SILEX and on planarized wafers from VTT.
WP4 – 2DM Component and PIC Fabrication:
Initial efforts involved short-loop definitions and mask design/testing for the three use cases. For the LIDAR sensor, SILEX and OMMA are optimising the waveguide platform. For the greenhouse gas sensor, SENSE ran simulations to define suitable waveguide dimensions and designed structures for testing key components. For the PDR, VTT and G&H collaborated on design specs and developed integration components for aligning light intensity with graphene detectors. Initial integration of graphene detectors is completed.
WP5 – Use Cases Integration and Validation:
This WP focuses on integrating and validating each use case.
• Use Case 1: Ground-based tests using an existing YSCAN system confirmed accurate trajectory reconstruction via SLAM and GNSS-Inertial fusion. Development is ongoing.
• Use Case 2: Preparations are underway, including coordination among SENSE, LiU, and BERT, and procurement of necessary equipment and materials.
• Use Case 3: G&H began testing and validation for PDR devices. Test setups for fibre-chip coupling have been optimized, and optical arrays were sourced to evaluate multiple outputs simultaneously.
WP1 – Requirements and Specifications:
The project reviewed existing system specs and proposed enhanced ones tailored to the needs of each application, prioritising factors like size for LIDAR, response time for greenhouse gas sensing, and spectral response for OCT. Tailored requirements for the three demonstrators were successfully defined, along with PIC design choices.
WP2 – 2D Materials Growth and Platform Development:
GSEMI supplied various graphene donor substrates to NTUA, which conducted DFT-based quantum-mechanical simulations to study graphene behaviour on receiver substrates and detachment processes from metallic donors. VTT optimised optical mode simulations for detector integration. First-generation 2D material and SOI platform qualification tests were completed, and initial wafer processing for graphene integration was successfully conducted by SILEX and VTT.
WP3 – 2D Material Digital Transfer and Integration:
NTUA began developing a laser direct transfer (LDT) station to meet graphene photodetector needs. The LIFT method was demonstrated as a fast, low-cost way to integrate 2D materials onto chips. Arrays of graphene pixels were successfully transferred and integrated into photodetector prototypes, now under evaluation by VTT. Material integrity was validated using advanced microscopy and spectroscopy techniques. GSEMI also achieved semi-dry monolayer graphene transfers on multiple 8-inch wafers from SILEX and on planarized wafers from VTT.
WP4 – 2DM Component and PIC Fabrication:
Initial efforts involved short-loop definitions and mask design/testing for the three use cases. For the LIDAR sensor, SILEX and OMMA are optimising the waveguide platform. For the greenhouse gas sensor, SENSE ran simulations to define suitable waveguide dimensions and designed structures for testing key components. For the PDR, VTT and G&H collaborated on design specs and developed integration components for aligning light intensity with graphene detectors. Initial integration of graphene detectors is completed.
WP5 – Use Cases Integration and Validation:
This WP focuses on integrating and validating each use case.
• Use Case 1: Ground-based tests using an existing YSCAN system confirmed accurate trajectory reconstruction via SLAM and GNSS-Inertial fusion. Development is ongoing.
• Use Case 2: Preparations are underway, including coordination among SENSE, LiU, and BERT, and procurement of necessary equipment and materials.
• Use Case 3: G&H began testing and validation for PDR devices. Test setups for fibre-chip coupling have been optimized, and optical arrays were sourced to evaluate multiple outputs simultaneously.
Next-2Digits goal is to establish wafer-scale heterogeneous integration technologies for 2D materials in the next generation of PICs and OEICs. In order to do this, the Next-2Digits project will directly integrate Graphene into PICs using semi-dry transfer and Laser Digital Transfer technologies.
In order to accomplish these objectives, it will advance the current state-of-the-art value chain of technologies, including a Si photonics platform fostering the direct integration of 2D materials, wafer-scale integration of 2D materials, 2D material-based PICs and OEICs, and 2DM-enabled applications:
1. A miniaturized LiDAR with an integrated graphene photodetector will be validated at TRL5 in an Unmanned Aerial Vehicle (UAV).
2. A PIC greenhouse gas sensor with high sensitivity and miniaturized footprint offering multi-sensing capability, validated in several biogas plants.
3. An on-chip polarization diversity receiver (PDR) offering extended bandwidth and high resolution will be used for biomedical optical coherence tomography (OCT) imaging in a cardiovascular application.
The Next-2Digits consortium has identified an exploitation plan focused on translating these advancements into commercial success.
Key exploitable results include the two transfer processes integrating graphene-on-wafer platforms tailored for application-specific PICs, lightweight FMCW LiDAR systems, nondispersive infrared (NDIR) sensors, and graphene photodetectors integrated on thick-SOI silicon photonics platforms.
Finally, the Next-2Digits project includes a structured approach to Intellectual Property (IP) management. This involves monitoring both external IP developments and internal results generated within the project. IP advisory services by AMI have supported partners in identifying, protecting, and managing their innovations. Notably, two detailed patentability searches have already been conducted, helping to assess the potential for securing patents and strengthening the consortium’s competitive position.
In order to accomplish these objectives, it will advance the current state-of-the-art value chain of technologies, including a Si photonics platform fostering the direct integration of 2D materials, wafer-scale integration of 2D materials, 2D material-based PICs and OEICs, and 2DM-enabled applications:
1. A miniaturized LiDAR with an integrated graphene photodetector will be validated at TRL5 in an Unmanned Aerial Vehicle (UAV).
2. A PIC greenhouse gas sensor with high sensitivity and miniaturized footprint offering multi-sensing capability, validated in several biogas plants.
3. An on-chip polarization diversity receiver (PDR) offering extended bandwidth and high resolution will be used for biomedical optical coherence tomography (OCT) imaging in a cardiovascular application.
The Next-2Digits consortium has identified an exploitation plan focused on translating these advancements into commercial success.
Key exploitable results include the two transfer processes integrating graphene-on-wafer platforms tailored for application-specific PICs, lightweight FMCW LiDAR systems, nondispersive infrared (NDIR) sensors, and graphene photodetectors integrated on thick-SOI silicon photonics platforms.
Finally, the Next-2Digits project includes a structured approach to Intellectual Property (IP) management. This involves monitoring both external IP developments and internal results generated within the project. IP advisory services by AMI have supported partners in identifying, protecting, and managing their innovations. Notably, two detailed patentability searches have already been conducted, helping to assess the potential for securing patents and strengthening the consortium’s competitive position.