Reconfigurable Electronic Devices Research Articles

Waveguide-integrated aluminum-MoTe2 Schottky photodetectors for the wavelength band extended to 2 µm.

Transition metal dichalcogenide (TMDC) materials with excellent optoelectronic properties have attracted much attention in the fields of reconfigurable electronic devices, next-generation FETs, and photodetectors (PDs). While normal TMDC PDs have a bandgap-limited absorption edge of ∼1.3 µm, metal-TMDC Schottky PDs based on internal photoemission provide an operation band extension strategy. In this study, we demonstrate that a TMDC PD can even operate at the wavelength band as long as 2.0 µm by judiciously choosing TMDC and metal materials to construct a low barrier height Schottky PD. Specifically, a silicon waveguide-integrated Al-MoTe2 Schottky PD was measured with responsivities of 18 mA/W and 5.5 mA/W at 1.6 µm and 2 µm, respectively. Meanwhile, the dark current is as low as 2 µA. The linear response can be maintained when the input optical power is in the mW scale. A measured 3 dB bandwidth is much larger than 1.75 MHz. These findings offer a promising avenue for expanding the detection range of the TMDC-based PDs with overall good performance in responsivity, bandwidth, sensitivity, and linearity.

Theoretical Studies on Controlling the Chirality of Helical Polarization Vortices in Ferroelectric Nanowires: Implications for Reconfigurable Electronic Devices

Theoretical Studies on Controlling the Chirality of Helical Polarization Vortices in Ferroelectric Nanowires: Implications for Reconfigurable Electronic Devices

Emerging reconfigurable electronic devices based on two‐dimensional materials: A review

AbstractAs the dimensions of the transistor, the key element of silicon technology, are approaching their physical limits, developing semiconductor technology with novel concepts and materials has been the main focus of scientific research and industry. In recent years, emerging reconfigurable technologies that offer device‐level run‐time reconfigurability have been explored and shown the potential to enhance device and circuit functions. Two‐dimensional (2D) materials possess exquisite electronic properties and provide a suitable platform for reconfigurable technology owing to their atomic‐thin thickness and high sensitivity to external electrical fields. In this review, we present an intensive survey of 2D‐material‐based devices with diverse reconfigurability, including carrier polarity, threshold voltage control, as well as multifunctional configurations enabled by 2D heterostructures. We discuss the working principles for these devices in detail and highlight the important figures of merit for performance improvement. We further provide a forward‐looking perspective on the opportunities and challenges of these reconfigurable devices based on 2D materials in the field of computing technologies.image

(Invited) Smart Nanomembranes for Multifunctional Sensors and Reconfigurable Electronics

Following the path of More than Moore requirements, functionalization and diversification of integrated circuits becomes an urgent topic. Integration of functions in a single chip is also an important issue in wearable and portable electronics. Smart nanomembranes, with thickness ranging from several to hundreds of nanometers, is considered as an ideal candidate in these circumstances for its flexibility. The word “smart” shows that these nanomembranes can perform sensing and actuating tasks by themselves, which largely reduces the complexity of flexible sensors and devices. The talk given here is focused on our recent progress in the development of smart nanomembranes for flexible sensors and reconfigurable electronics. Combined with sensing-type smart nanomembranes as palladium and hydrogel, we designed a multifunctional soft platform to detect different kinds of signals (e.g. gas and humidity), which can be integrated into a smart digital dust device. Furthermore, smart nanomembranes with actuation properties were applied in reconfigurable electronic devices. These nanomembrane-based devices are able to be stabilized in different configurations to provide particular and switchable electronic functions. These investigations highlight the great potential of smart nanomembranes in flexible electronics. And their unique sensing and actuating properties paves the way to intelligent robots in micro and nanoscale.

Designing Gold Binding Peptides: Modelling and Experiment at the Bio-Abiotic Interface

The interface of biological and abiological material is an area of intense interest, touching on a widespread application space of sensors, bioelectronics, designer coatings, self-healing materials. Building upon our work in reconfigurable electronic devices, part of our efforts were focused on engineering E. coli to display metal binding peptides using a bacterial display system, eCPX. Here, we present our efforts in understanding cell binding to Au(111) surfaces as well as gold nanoparticles (AuNPs) through a series of known and designed gold binding peptides (GBPs) that have been engineered into eCPX. First, we demonstrate that integration of specific GBPs into the E. coli outer membrane protein increases binding to both Au(111) surfaces and AuNPs, that the binding to gold is selective, and is influenced by interactions with specific amino acids. Second, from molecular dynamics (MD) simulations of select GBPs on Au(111), we show that interaction energies between the peptides and surface correlate with experimental data, and that both thermodynamic and entropic effects play a role in binding. And finally, we demonstrate a novel fragment-based computer-aided biomaterial design approach using Au(111) as a proof of concept. These findings will be discussed in the greater context of our work in transformational synthetic biology for military environments.

(Invited) Wafer-Scale Integration of 2D TMD Heterostructures of Controlled Layer Orientation on Arbitrary Substrates Towards Mechanically-Reconfigurable Electronic Devices

Advancements of modern electronics have demanded to incorporate a diverse set of additional functionalities into device platforms such as high mechanical deformability and improved material/process sustainability. Traditional silicon (Si) wafers-based device manufacturing is intrinsically limited in realizing such novel aspects owing to their rigid/bulky nature as well as complex and unsustainable process schemes. Two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors are highly promising owing to their extremely large mechanical flexibility and near atom thickness coupled with van der Waals (vdW) attraction-enabled relaxed assembly requirement. Major challenges for realizing such opportunities for emerging electronics have been associated with a lack of reliable manufacturing methods to precisely separate 2D TMD layers from original growth wafers and integrate them on desired functional substrates in a controllable, scalable, and sustainable manner. In this talk, I will discuss recent efforts in my group on exploring viable manufacturing strategies to assemble wafer-scale 2D TMD layers of heterogeneously tailored components on arbitrary substrates. We grew various 2D TMD layers of controlled layer orientation on specially-treated growth substrates with high hydrophilicity or water solubility via a chemical vapor deposition (CVD) process. By taking advantage of the large surface energy contrast between growth substrates vs. grown 2D TMDs, we precisely peel off wafer-scale 2D TMD layers from their original substrates using water preserving their intrinsic structural/chemical integrity. We then integrate them on substrates of virtually unrestricted kinds and shapes in a layer-by-layer fashion, realizing heterogeneously-assembled wafer-scale 2D TMDs layers on a variety of exotic substrates impossible with any conventional approaches. The achieved material quality has been characterized via extensive microscopy/spectroscopy techniques, and the original substrates have been sustainably recycled for sequential growth and integration. Several demonstrations of 2D TMDs-enabled mechanically reconfigurable electronic devices will be presented, which will be impossible with any other traditional materials. This novel manufacturing strategy is believed to greatly broaden the applicability of 2D TMDs in emerging areas of electronics such as three-dimensionally conformal electronic devices of unconventional forms factors.

Characterization and control of vortex and antivortex domain defects in quadrilateral ferroelectric nanodots

Ferroelectric nanostructures have recently attracted considerable research interests for the discovery of novel topological dipole states. However, currently the preparation of high-quality nanodot arrays remains challenging, precluding the clear characterization of the dipole states in the nanodots. Combining pulsed laser deposition method with circular anodic aluminum oxide template, we reported an unexpected growth of high crystalline quality $\mathrm{PbZ}{\mathrm{r}}_{0.52}\mathrm{T}{\mathrm{i}}_{0.48}{\mathrm{O}}_{3}$ nanodot array in quadrilateral shape with size being \ensuremath{\sim}80 nm. Piezoresponse force microscopy measurement on various regions of the sample shows that the nanodots form rather diverse in-plane domain patterns, with the appearance of abundant topological domain defects including flux-closure vortices, center-divergent vortices, center-convergent vortices, and antivortices. A deterministic control of the domain structure of the nanodots via applying an electric field is further achieved. The nanodots were found to favor a center-divergent vortex pattern under negative tip bias, although the domain patterns of the nanodots at the as-grown state are different. Phase field simulations were performed to reproduce the experimental observation, and our results indicate that the screening condition of the nanodots is far from the ideal ones assumed in previous theoretical modellings. The nanodots are potentially useful in developing multi-state and reconfigurable electronic devices.

Three-dimensional imaging of vortex structure in a ferroelectric nanoparticle driven by an electric field

Topological defects of spontaneous polarization are extensively studied as templates for unique physical phenomena and in the design of reconfigurable electronic devices. Experimental investigations of the complex topologies of polarization have been limited to surface phenomena, which has restricted the probing of the dynamic volumetric domain morphology in operando. Here, we utilize Bragg coherent diffractive imaging of a single BaTiO3 nanoparticle in a composite polymer/ferroelectric capacitor to study the behavior of a three-dimensional vortex formed due to competing interactions involving ferroelectric domains. Our investigation of the structural phase transitions under the influence of an external electric field shows a mobile vortex core exhibiting a reversible hysteretic transformation path. We also study the toroidal moment of the vortex under the action of the field. Our results open avenues for the study of the structure and evolution of polar vortices and other topological structures in operando in functional materials under cross field configurations.

Thermally Triggered Mechanically Destructive Electronics Based On Electrospun Poly(\u03b5-caprolactone) Nanofibrous Polymer Films

Electronics, which functions for a designed time period and then degrades or destructs, holds promise in medical implants, reconfigurable electronic devices and/or temporary functional systems. Here we report a thermally triggered mechanically destructive device, which is constructed with an ultra-thin electronic components supported by an electrospun poly(ε-caprolactone) nanofibrous polymer substrate. Upon heated over the melting temperature of the polymer, the pores of the nanofibers collapse due to the nanofibers’ microscopic polymer chain relaxing and packing. As a result, the polymer substrate exhibits approximately 97.5% area reduction. Ultra-thin electronic components can therefore be destructed concurrently. Furthermore, by integrating a thin resistive heater as the thermal trigger of Joule heating, the device is able to on-demand destruct. The experiment and analytical results illustrate the essential aspects and theoretical understanding for the thermally triggered mechanical destructive devices. The strategy suggests a viable route for designing destructive electronics.

Liquid metal enabled microfluidics.

Several gallium-based liquid metal alloys are liquid at room temperature. As 'liquid', such alloys have a low viscosity and a high surface tension while as 'metal', they have high thermal and electrical conductivities, similar to mercury. However, unlike mercury, these liquid metal alloys have low toxicity and a negligible vapor pressure, rendering them much safer. In comparison to mercury, the distinguishing feature of these alloys is the rapid formation of a self-limiting atomically thin layer of gallium oxide over their surface when exposed to oxygen. This oxide layer changes many physical and chemical properties of gallium alloys, including their interfacial and rheological properties, which can be employed and modulated for various applications in microfluidics. Injecting liquid metal into microfluidic structures has been extensively used to pattern and encapsulate highly deformable and reconfigurable electronic devices including electrodes, sensors, antennas, and interconnects. Likewise, the unique features of liquid metals have been employed for fabricating miniaturized microfluidic components including pumps, valves, heaters, and electrodes. In this review, we discuss liquid metal enabled microfluidic components, and highlight their desirable attributes including simple fabrication, facile integration, stretchability, reconfigurability, and low power consumption, with promising applications for highly integrated microfluidic systems.

Reconfigurable sticker label electronics manufactured from nanofibrillated cellulose-based self-adhesive organic electronic materials

Low voltage operated electrochemical devices can be produced from electrically conducting polymers and polyelectrolytes. Here, we report how such polymers and polyelectrolytes can be cast together with nanofibrillated cellulose (NFC) derived from wood. The resulting films, which carry ionic or electronic functionalities, are all-organic, disposable, light-weight, flexible, self-adhesive, elastic and self-supporting. The mechanical and self-adhesive properties of the films enable simple and flexible electronic systems by assembling the films into various kinds of components using a “cut and stick” method. Additionally, the self-adhesive surfaces provide a new concept that not only allows for simplified system integration of printed electronic components, but also allows for a unique possibility to detach and reconfigure one or several subcomponents by a “peel and stick” method to create yet another device configuration. This is demonstrated by a stack of two films that first served as the electrolyte layer and the pixel electrode of an electrochromic display, which then was detached from each other and transferred to another configuration, thus becoming the electrolyte and gate electrode of an electrochemical transistor. Further, smart pixels, consisting of the combination of one electrochromic pixel and one electrochemical transistor, have successfully been manufactured with the NFC-hybridized materials. The concept of system reconfiguration was further explored by that a pixel electrode charged to its colored state could be detached and then integrated on top of a transistor channel. This resulted in spontaneous discharging and associated current modulation of the transistor channel without applying any additional gate voltage. Our peel and stick approach promises for novel reconfigurable electronic devices, e.g. in sensor, label and security applications.

Enhanced electric conductivity at ferroelectric vortex cores in BiFeO3

T opological defects in ferroic materials are attracting much attention both as a playground of unique physical phenomena and for potential applications in reconfigurable electronic devices. Here, we explore electronic transport at artificially created ferroelectric vortices in BiFeO3 thin films. The creation of one-dimensional conductive channels activated at voltages as low as 1 V is demonstrated. We study the electronic as well as the static and dynamic polarization structure of several topological defects using a combination of first-principles and phase-field modelling. The modelling predicts that the core structure can undergo a reversible transformation into a metastable twist structure, extending charged domain walls segments through the film thickness. The vortex core is therefore a dynamic conductor controlled by the coupled response of polarization and electron‐mobile-vacancy subsystems with external bias. This controlled creation of conductive one-dimensional channels suggests a pathway for the design and implementation of integrated oxide electronic devices based on domain patterning.