2D materials and specifically Transition Metal Dichalcogenides have received much attention as photoactive materials in photodetectors. These materials possess attractive properties, including a direct bandgap in the visible range and mechanical resilience to strain, making them an attractive material for flexible photodetectors. Here we demonstrate 4x4 pixel photodetector arrays on flexible and non-flexible substrates based on mechanically exfoliated flakes of MoS2. The arrays have a minimum pitch between array pixels of 9.5 µm in both vertical and horizontal directions. Demonstrating, to our knowledge, the densest 2D material based photodetector array to date.
This study presents a vanadium carbide (V2C) mid-IR photodetector. Drop casting and spin coating a silicon substrate with a thin silicon oxide layer produced the V2C photodetector. Isopropyl alcohol and nitrogen gas drying increased material quality. E-beam lithography and metal deposition of Au/Ti contacts on V2C flakes carefully made electrical connections. Electrical bias and 2 μm laser light evaluated the V2C photodetector's dark current and photocurrent responses. Photocurrent response changed dramatically, matching FTIR spectroscopy findings. V2C's peak responsivity of 2.65 A/W demonstrated mid-IR photodetection. To test scalability, we created devices with 2-5 μm channels. For specialized sensing, photocurrent increases with channel length. On-chip waveguides and photonic circuits might use V2C photodetectors. V2C's mid-IR photodetector exhibits its promise as a cutting-edge optoelectronics and integrated photonics material. This finding expands mid-IR-sensing photodetector technology.
As Internet-of-Things (IoT) devices continue to grow rapidly in number, developing energy-efficient memory solutions has become critically important. This paper introduces an innovative Phase Change Memory (PCM) architecture that can significantly reduce memory energy consumption in IoT devices. After highlighting the energy-inefficiency of current memory designs, we explore the possibilities of leveraging PCM. We demonstrate that the benefits of exploiting PCM are dependent on the working frequency of the CPU and show how PCM can surpass devices with SRAM and DRAM. As a replacement candidate for FLASH, PCM can also be utilized instead of SRAM and DRAM. We also demonstrate that based on the application we can also save more energy. Ongoing work focuses on deployment of this application dependency and enhancing energy efficiency of devices using PCM. Our PCM innovation enables improved functionality lifetimes for non-volatile IoT edge devices. This represents a major advance towards realizing widespread integration of photonics and electronics in IoT hardware.
Binarized neural networks offer substantial reductions in memory and computational requirements compared to full precision networks. However, conventional CMOS-based hardware implementations still face challenges with resilience for deployment in harsh environments like space. This paper proposes an optical XOR-based accelerator for binarized neural networks to enable low power and resilient operation. The optical logic gates rely on wavelength-specific intensity propagation rather than absolute intensity levels. This provides inherent robustness against fabrication process variations and high energy particle strikes. Simulations of an optical hardware prototype for XNOR-Net show the accelerator achieves 1.2 μs latency and 3.2 mW power. The binarized network maintained 2-4% accuracy degradation compared to the full precision baseline on MNIST and CIFAR-10. The proposed optical accelerator enables efficient and resilient deployment of binarized neural networks for harsh environment applications like spacecraft and satellites.
Here, we're pioneering a novel approach in photonics, targeting the development of ultra-low power communication systems and advanced sensing technologies. Central to our strategy is the implementation of a unique zig-zag structure, designed to achieve femtojoule (fJ) per bit communication efficiency. A key innovation in our approach is the integration of unidirectional coupling through on-chip isolation, seamlessly connecting a Transverse Coupled Cavity VCSEL (TCCVCSEL) to the modulator and then to a waveguide. This project has wide-ranging implications, extending beyond just creating new devices. It's geared towards establishing a robust III/V platform, serving as a cornerstone in the field of photonics and integrated circuit technology. Our work is poised to catalyze advancements in high-speed, low-power photonic systems, potentially setting new benchmarks in the industry.
Here we demonstrate Tungsten Disulfide (WS2) integrated silicon nitride photodetector, and we experimentally tested the responsivity of 0.32 A/W. The spectroscopic results using PL and Raman mapping were used to understand strain effect on excitonic bandgap by studying characteristics like excitons, trions, E12g, A1g and opto-electronic response. We show high potential for flexible sensors and high spectral resolution sensing.
This study aimed to develop and implement a novel data encryption method that utilizes a hybrid processor Photonic Tensor Core and chaotic oscillators to generate an "infinite key" suitable for use with common encryption algorithms. To demonstrate its effectiveness, we built a prototype consisting of a hybrid processor simulator, chaotic oscillators, a key generator, an encryption/decryption tool, and a graphical user interface. We tested and inspected the tool using custom scripts and a graphical user interface, which allows two separate users to compare their respective results. In upcoming studies, we plan to expand the tool to accommodate multiple participants and develop a hardware prototype.
The rapid development of nanophotonic technologies has put forward higher requirements for optoelectronic devices, including ultra-small footprints, high-speed operation, high efficiency, and low power consumption. Optoelectronics based on emerging materials can provide the material framework that can keep pace with future technological demands. Here we will share our latest innovations and device demonstrations of using low-dimensional materials towards discovering high-performance photodetector and electro-optic modulator performances. We will share the concept of strainoptronics enabling to engineer a plurality of material properties (bandgap, workfunction, mobility) and show how a Transition-Metal Dichalcogenides (TMDC)-based efficient photodetector can be realized using MoS2 on a Silicon photonic platform. Furthermore, using scaling-length-theory, we show our roadmap and results of high gain-bandwidth product photodetectors using a metal slot atop a silicon photonic waveguide towards optimizing the carrier-lifetime to transit time ratio. These devices were enabled by a novel 3D-like 2D material transfer system, which also enabled us to demonstrate a 2D material PN junction photodetector operating at zero bias, thus leading to extremely low dark currents and hence very efficient noise-equivalent powers. Finally, we show our latest work on ITO-thin film electro-optic modulators with 40 GHz 3dB roll-off, requiring just 200 meV of the drive voltage. Further development of the modulator platform shows the potential of a 100 GHz fast MZI modulator with a footprint that is 1,000 more compact than standard Silicon photonics and 10,000 more compact compared to Lithium Niobite.
Here we present our latest PIC-integrated TMD-based slot-enhanced photodetector. The
metallic slot enhances the light-matter-interaction and hence absorption into the semiconductor TMD layer.
Unlike Graphene detectors, this device based on a 1+eV wide Eg detector (MoTe2) shows a low dark-current
Of 100’s pA (i.e. 3 orders of magnitude lower than graphene). Utilizing the plasmonic slot allows to harness
scaling effects known from FETs, and reduce carrier transit times. Thus, we demonstrate 10GHz roll-offs
despite a rather low mobility. We further show that the short-channel allows for near-ballistic transport, and
more importantly high gain-bandwidth-products (GPB), which scales with the source-drain distance squared.
The combination of a TMD semiconductor with a slot for short transit times, enables we new class of
efficient yet compact PIC-integrated detectors offering high GBP.
KEYWORDS: Photodetectors, Heterojunctions, Sensors, Signal detection, Near infrared, Visible radiation, Three dimensional sensing, Signal to noise ratio, Remote sensing, Physics
Here, we demonstrate a 2D p–n van der Waals heterojunction photodetector constructed by vertically stacking p-type and n-type few-layer indium selenide (InSe) 2D flakes. This heterojunction charge-separation-based photodetector shows a three-fold enhancement in responsivity at near-infrared spectral region (980 nm) as compared to a photoconductor detector based on p- or n-only doped regions, respectively. We show, that this junction device exhibits self-powered photodetection operation and hence enables few pA-low dark currents, which is about 3-4 orders of magnitude more efficient than state-of-the-art foundry-based devices. Such capability opens doors for small signal-to-noise environments and low photon-count detectability without having to rely on external gain. We further demonstrate millisecond response rates in this sensitive zero-bias voltage regime.
In this work, we demonstrate a photodetector (PD) based on heterogeneous integration of Few-layer MoTe2 integrated on planarized and non-planarized Si waveguide operating at 1550 nm. Under a strong local tensile strain (4%), the bandgap of few layers MoTe2 shifts from 1 eV to 0.8 eV, enabling higher responsivity as compared to unstrained one.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.