Optical Transistor Research Articles

Tuning the antiaromatic character and charge transport of pentalene-based antiaromatic compounds by substitution

Substituting electron-donating and electron-accepting substituents on antiaromatic pentalene cores can significantly tune the optical absorption, energy levels, antiaromaticity, and transistor switch-on behavior.

High-Performance Aie-Active Poly(Ether Sulfone)S as Polymeric Electret for Energy-Saving Genuine Photonic Transistor Memory

High-Performance Aie-Active Poly(Ether Sulfone)S as Polymeric Electret for Energy-Saving Genuine Photonic Transistor Memory

Modeling optical transistor based on the pole effect of parity-time symmetric coupled cavities

In order to achieve a new kind of optical transistor model, we construct a parity-time (PT) symmetry coupled cavity structure. The gain cavity G is made of semiconductor InGaAsP doped with quantum well and the loss cavity is made of the same material as G but periodically inserted by graphene sheets. Through a parameter optimizing, the structure reaches the PT-symmetry pole state with a huge transmittance. The voltage on the graphene sheets as an input signal can modulate the pole state and results in an amplification output of transmittance. Through proper static working points, the structure can achieve the amplification in phase, out phase and of doubling frequency.

Photovoltaic‐Ferroelectric Materials for the Realization of All‐Optical Devices

AbstractFollowing how the electrical transistor revolutionized the field of electronics, the realization of an optical transistor in which the flow of light is controlled optically should open the long‐sought era of optical computing and new data processing possibilities. However, such function requires photons to influence each other, an effect which is unnatural in free space. Here it is shown that a ferroelectric and photovoltaic crystal gated optically at the onset of its bandgap energy can act as an optical transistor. The light‐induced charge generation and distribution processes alter the internal electric field and therefore impact the optical transmission with a memory effect and pronounced nonlinearity. The latter results in an optical computing possibility, which does not need to operate coherently. These findings advance efficient room temperature optical transistors, memristors, modulators and all‐optical logic circuits.

Self‐Assembled Nanostructures of Quantum Dot/Conjugated Polymer Hybrids for Photonic Synaptic Transistors with Ultralow Energy Consumption and Zero‐Gate Bias

AbstractHerein, it is reported the influence of solution processing and treatments, such as adding marginal solvent, ultrasonication, and UV treatment, on the resulting perovskite (CsPbBr3) quantum dot (QD)/poly(3‐hexylthiophene) (P3HT) composite nanofibril films (CNFs) to improve the charge dissociation and photonic synaptic performance. A photonic synaptic transistor with CNFs can perform fundamental functions, including short‐term plasticity, long‐term plasticity, spike‐number‐dependent, and spike‐time‐dependent plasticity, to mimic sensing, computing, and memory functions. Notably, a synaptic device with CNFs presents an ultralow energy consumption of 0.18 fJ and zero‐gate operation. The superior performance of synaptic devices with CNFs can be attributed to two factors: (i) homogeneous axial distribution of the QDs and (ii) the formation of P3HT nanofibrils and co‐aggregates. Therefore, enhanced interfacial charge transfer between QDs and P3HT, ensuring decent carrier transport capability, is achieved. Collectively, the composite artificial synapse successfully provides an effective guide that offers a new perspective for the fabrication of one‐dimensional self‐assembled nanostructure‐based artificial synapses emulating human‐like memory, neuromorphic computing, and artificial intelligent systems.

Volatility Transition from Short‐Term to Long‐Term Photonic Transistor Memory by Using Smectic Liquid Crystalline Molecules as a Floating Gate

AbstractRod‐like molecules with liquid crystalline phase transitions show highly ordered stacking and orientation, which is promising as the floating gate electret in high‐performance photonic field‐effect transistor (FET) memory. In this work, a series of rod‐like molecules, alkyl‐dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (Cn‐DNTT), are investigated with a smectic liquid crystalline phase transition. The photonic FET memory featuring these rod‐like molecules is correlated with their morphology and crystallographic properties. A volatility transition from short−term to long−term memory behavior is found by utilizing the smectic liquid crystalline phase transitions (SmX, X = H, K, E) to orient the stacking in the floating gate. Accordingly, the annealed 2,9‐didecyldinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (C10‐DNTT) polycrystalline film with the optimized alkyl chain length achieved preferential end‐on orientation associated with the herringbone‐type stacking to store charges during photowriting, along with effective charge tunneling for the trapped charges during electrical erasing. Therefore, the resultant photonic FET memory provided a superior ON/OFF current ratio of up to 105 with retention of 104 after 104 s. The results demonstrate that rod‐like molecules with smectic liquid crystalline phase and highly ordered orientation have great potentials for developing high‐performance photonic FET memory.

InP3 Monolayer as a Promising 2D Sensing Material in SF6 Insulation Devices.

In this letter, we perform a first-principles study on the adsorption performance of the InP3 monolayer upon three SF6 decomposed species, including SO2, SOF2, and SO2F2, to investigate its potential as a resistance-type, optical or field-effect transistor gas sensor. Results indicate that the InP3 monolayer exhibits strong chemisorption upon SO2 but weak physisorption upon SO2F2. The most admirable adsorption behavior is upon SOF2, which provides a favorable sensing response (−19.4%) and recovery property (10.4 s) at room temperature as a resistance-type gas sensor. A high response of 180.7% upon SO2 and a poor one of −1.9% upon SO2F2 are also identified, which reveals the feasibility of the InP3 monolayer as a resistance-type sensor for SO2 detection with recycle use via a heating technique to clean the surface. Moreover, the InP3 monolayer is a promising optical sensor for SO2 detection due to the obvious changes in adsorption peaks within the range of ultraviolet and is a desirable field-effect transistor sensor for selective and sensitive detection of SO2 and SOF2 given the evident changes of QT and Eg under the applied electric field.

Liquid Crystalline Rylenediimides with Highly Order Smectic Layer Structure as a Floating Gate for Multiband Photoresponding Photonic Transistor Memory

AbstractWith the growing demands of light fidelity technology, photonic transistor memory has gained considerable attention for next‐generation optoelectronic devices. In this work, alkylated rylenediimides of 2,9‐diphenethylanthra[2,1,9‐def:6,5,10‐d“e”f]diisoquinoline‐1,3,8,10(2H,9H)‐tetraone (C8‐PDI) and 2,7‐dioctylbenzo[lmn][3,8]phenanthroline‐1,3,6,8(2H,7H)‐tetraone (C8‐NDI), and pyromellitic diimide of 2,6‐dioctylpyrrolo[3,4‐f]isoindole‐1,3,5,7(2H,6H)‐tetraone (C8‐PMDI) have been used as floating gate electrets in the photonic field‐effect transistor‐type memory. The structure‐optics‐performance relationship of these rod‐like molecules has been systematically studied, and the memory device exhibited a decent response to photowriting and electrical erasing processes, owing to the 3D ordered smectic layer structure and brickwork stacking. Therefore, an evenly distributed photogating moiety, efficient exciton dissociation associated with decent carrier tunneling and charge trapping can be obtained. Among them, the sought‐after C8‐NDI presents favorable energy level alignment, multiband photoresponding, and an optimal block ratio. The fabricated photonic memory with C8‐NDI electret presented a remarkable memory switchability with a memory ratio of 104 and a stable memory ratio of 105 over 10,000 s. To the best of knowledge, this is the first work to utilize rylenediimides based liquid crystals as an efficient charge blocking electret, and these findings open an avenue for designing rod‐like molecules with highly ordered liquid crystalline properties in the ultrafast photomemory devices.

Manipulation of optical nonreciprocity in hot atom-cavity system

Hot atoms can exhibit non-magnetic optical non-reciprocal transmission due to their chiral properties, which are characteristic of most alkali metal atoms. In fact, the nonreciprocity in hot atoms depends on the propagation direction of the coupling field due to the Doppler effect. Herein, the reciprocal to non-reciprocal conversion based on the single- and double-dark states is realized by controlling the bidirectional coupling fields in a three-level electromagnetically induced transparent medium coupled with a ring cavity. Tuning the frequency difference between the two coupling fields causes the multi-frequency-channel reciprocity and nonreciprocity manipulation to occur. The experimental proof can be applied to quantum communications and quantum networks, such as optical transistors, all-optical switching or routing and logic gate operation.

Highly Efficient Photo‐Induced Recovery Conferred Using Charge‐Transfer Supramolecular Electrets in Bistable Photonic Transistor Memory (Adv. Funct. Mater. 40/2021)

Supramolecular Electrets In article number 2102174, Wen-Chang Chen and co-workers develop charge transfer-based supramolecular electrets comprising poly(1-pyrenemethyl methacrylate) and 7,7,8,8-tetracyanoquinodimethane for photonic field-effect transistor memory. The fabricated devices exhibit superior memory switchability using electrical/photoprograming under UV and green light, showing a broad memory window of 34 V and memory ratio of over 106 after 104 s.

Localization of Light in Photonics Lattices for All-Optical Representation of Binaries

In this paper we present a novel conceptual method for all optical representation of binary numbers that could be used for all-optical binary logic components in optical digital computing, as well as for other applications. The new concept is based on effect of localization of light in specially designed binary photonics lattices whose central parts resemble the represented binaries, and the localizations occur due to breaking periodicities of the lattices. The proposed structures can be made with integrated photonics on-chip that are highly programmable and controllable. Most significantly, the working principle of the novel method doesn’t require nonlinear interaction between light and material, which is the most serious obstacle in the conventional method that uses optical transistors whose mechanism relies mainly on optical nonlinearity. We will discuss some technical challenges in developing the components.

Realizing fast photoinduced recovery with polyfluorene‐block‐poly(vinylphenyl oxadiazole) block copolymers as electret in photonic transistor memory devices

AbstractPhotonic field‐effect transistor (FET) memory devices offer unique advantages owing to their solution processability, low cost production, and their lightweight and structural flexibility. Despite the plethora of research demonstrated the photon based programming process, limited reports are available for photoinduced recovery mechanism in such devices. To investigate the influence of polymer electret design on photonic memory performance, poly(9,9‐dioctylfluorene) (PFO)–block–poly (vinylphenyl oxadiazole) (POXD) conjugated block copolymers were employed to a photonic FET memory with n‐type semiconducting channel. The studied device exhibited bistable ON/OFF current states after electrical programming and photoinduced recovery (erasing) processes. The device operating mechanism was elaborated by comparing the device performance with respective electrets of PFO‐b‐POXD and PFO‐b‐polystyrene (PS) and PFO homopolymer. We found that PFO‐b‐POXD can efficiently generate photoexciton under UV illumination to neutralize the trapped hole, and assuage the hole trapping propensity of PFO segment, simultaneously. By optimizing the POXD content in the block copolymer, a decent memory ratio (ION/IOFF) of ~105 was achieved after 104 s, indicating its superior long‐term stability and data discernibility. This research shows the judicious strategy to design polymer electret for photonic memory, and it opens up the possibility of developing photonic memory, human perception and futuristic communication systems using simple, convenient and reliable optoelectronic technique.

Pd-doped SnP3 monolayer: A new 2D buddy for sensing typical dissolved gases in transformer oil

Dissolved gas analysis (DGA) is a workable and simple manner to evaluate the operation status of a transformer. In this paper, we investigated the adsorption performance of Pd-doped SnP3 (Pd-SnP3) monolayer upon three typical dissolved gases, including H2, CH4 and C2H2, using first-principles theory. The electronic behavior, dielectric function and work function were all considered to explore its potential as a chemical gas sensor for sensing application. Results indicated that Pd-doping is kind of n-doping for the pristine SnP3 surface and significantly enhances its adsorption performance upon three gases. Pd-SnP3 monolayer behaves physisorption upon H2 and CH4 with adsorption energy (Ead) of −0.64 and −0.65 eV, respectively, but chemisorption upon C2H2 with Ead of −1.21 eV. For sensing application, we found that Pd-SnP3 monolayer is a promising candidate as a resistance-type, optical or field electron transistor gas sensor to sensitively detect H2 and C2H2, and the electrical response for resistance-type sensor would be 93.87% and 314.29%, respectively. Our calculations aim to propose novel 2D buddy for DGA application, which is meaningful to realize the status-monitoring of the transformers and extend the exploration of SnP3-based material in many fields.

Thin Films Growth of SnO_2:F/CdS/CdTe, and Studies of Their Physical and Optical Properties using Spray Pyrolysis Techniques

Fluorine doped tin oxide, Cadmium Sulphide and Cadmium Telluride thin films have been deposted on Soda Lime glass substrate at respectively by spray pyrolysis (SP) technique and are important semiconductor materials in optoelectronic devices such as optical sensors, light-emitting diodes, transistors and photovoltaic cells. thin films were characterized by various techniques such as X-ray diffraction, SEM and optical studies. X-ray diffraction measurements show that the deposited was found to be of cassiterite type with tetragonal rutile structure, observation of peaks of different planes on an X-ray diffraction graph of thin film showed that film obtained were cubic structure. The main peak value of thin film is seen at , which is the characteristic peak of the compound and the film structure was obtained at the major peak indicating the preferred orientation of films along direction. This confirms the formation of thin film, with (111) as the strongest preferred plane of orientation. The surface morphology of the thin films was analysed by scanning electron microscopy (SEM). The optical energy band gap of thin films are determine The results showed that the prepared FTO, CdS and CdTe films can be used in solar energy applications.

Photonic Synaptic Transistor Based on P-Type Organic Semiconductor Blending With N-Type Organic Semiconductor

Neuromorphic computing, with information sensing, processing, and storage capabilities, is driving the development of a new generation of artificial intelligence (AI). Photonic synaptic devices are essential components for improving information processing efficiency owing to their advantages of a high propagation speed, low latency, and large bandwidth. In this study, a photonic synaptic transistor simply based on p-type organic semiconductor blending with n-type organic semiconductor was fabricated via simple solution process in which only light was used to control the enhancement and inhibition of the synaptic conductance. The device can simulate fundamental synaptic properties. Additionally, the coordination between light stimulation and electrical stimulation was investigated, and the results show that light-pulse stimulation is beneficial for increasing the response current simulated by electrical pulses. This work represents a significant step towards the realization of high-efficiency AI electronics.

Highly Efficient Photo‐Induced Recovery Conferred Using Charge‐Transfer Supramolecular Electrets in Bistable Photonic Transistor Memory

AbstractDonor–acceptor type polymers and supramolecules are promising electrets in photonic field‐effect transistor (FET)‐type memory because of their diversified polymer‐structure design and favorable mechanical tolerance. Using intermolecular association, supramolecule electrets can surpass donor–acceptor type polymers with versatile facile combining processes. Currently, there has been no application of charge‐transfer (CT) supramolecules in electrets of photonic FET memory devices. Herein, a novel series of CT‐based supramolecular electrets comprising poly(1‐pyrenemethyl methacrylate) (PPyMA) and 7,7,8,8‐tetracyanoquinodimethane (TCNQ) is used to elucidate the effect of CT on photonic FET memory. Accordingly, memory devices based on the supramolecular electret with an equimolar content of pyrene and TCNQ exhibit superior bistable memory switchability using electrical/photoprograming with UV (365 nm) and green light (525 nm). This shows a broad memory window of 34 V and favorable memory ratio of over 106 after 104 s. The memory performance can be attributed to the favorable molecular association and dispersion between pyrene and TCNQ in the solid state. The results provide evidence that CT‐based supramolecular electrets warrant applications in optoelectronic applications.

Spectrum‐dependent photonic synapses based on 2D imine polymers for power‐efficient neuromorphic computing

Abstract2D polymers (2DPs) have attracted increasing interests in sensors, catalysis, and gas storage applications. Furthermore, 2DPs with unique band structure and tunable photophysical properties also have immense potential for application in photonic neuromorphic computing. Here, photonic synaptic transistors based on 2DPs as the light‐tunable charge‐trapping medium are developed for the first time. The resulted organic transistors can successfully emulate common synaptic functions, including excitatory postsynaptic current, pair‐pulse facilitation, the transition of short‐term memory to long‐term memory, and dynamic filtering. Benefitting from the high photosensitivity of the 2DP, the devices can be operated under a low operating voltage of −0.1 V, and achieve an ultralow energy consumption of ~0.29 pJ per event. In addition, the heterostructure formed between the 2DP and organic semiconductor enables spectrum‐dependent synaptic responses, which facilitates the simulation of visual learning and memory processes in distinct emotional states. The underlying mechanism of spectrum‐dependent synaptic‐like behaviors is systematically validated with in situ atomic force microscopy based electrical techniques. The spectrum‐enabled tunability of synaptic behaviors further promotes the realization of optical logic functions and associative learning. This work inspires the new application of 2DPs in photonic synapses for future neuromorphic computing.image

Steep-Slope Gate-Connected Atomic Threshold Switching Field-Effect Transistor with MoS2 Channel and Its Application to Infrared Detectable Phototransistors.

For next‐generation electronics and optoelectronics, 2D‐layered nanomaterial‐based field effect transistors (FETs) have garnered attention as promising candidates owing to their remarkable properties. However, their subthreshold swings (SS) cannot be lower than 60 mV/decade owing to the limitation of the thermionic carrier injection mechanism, and it remains a major challenge in 2D‐layered nanomaterial‐based transistors. Here, a gate‐connected MoS2 atomic threshold switching FET using a nitrogen‐doped HfO2‐based threshold switching (TS) device is developed. The proposed device achieves an extremely low SS of 11 mV/decade and a high on‐off ratio of ≈106 by maintaining a high on‐state drive current due to the steep switching of the TS device at the gate region. In particular, the proposed device can function as an infrared detectable phototransistor with excellent optical properties. The proposed device is expected to pave the way for the development of future 2D channel‐based electrical and optical transistors.

Graphene-gated GaAs OPFET photodetector and oscillator for 5G applications

With the advancement of technology, the RF communication bandwidth is switching towards 5G and 6G communications. To relieve the congestion of traffic imposed on RF communication, operating in the optical domain or integrating RF and optical communication is imperative. The core components in this scenario are the oscillators as transmitters and photodetectors as receivers. These devices should be capable of high-speed and high-gain operation simultaneously. In this paper, the potential of graphene-gated GaAs front-illuminated OPFET (Optical Field Effect Transistor) as oscillator and detector towards 5G applications is explored. The OPFET device exhibits an oscillation frequency of 1.63 GHz to 1.8 GHz, tuned with optical illumination. The gain can be varied between 3.94 dB to 4.5 dB at the oscillation frequency. Under photodetection mode of operation, the device exhibits a maximum 3-dB bandwidth of 2.234 GHz, an fT of 5.33 GHz at the bandwidth frequency, and a responsivity of 3.3 × 106 A/W at a photon flux density of 1019/m2-s. A drain bias voltage of 3.94 V and a gate bias voltage of 0 V are applied in both cases. The device responses are contrasted with that of the Au (gold) gated OPFET. The explored devices have great potential for sub-6 GHz 5G applications.

Comprehensive Non-volatile Photo-programming Transistor Memory via a Dual-Functional Perovskite-Based Floating Gate.

Photonic transistor memory has received increasing attention as next-generation optoelectronic devices for light fidelity (Li-Fi) application due to the attractive advantages of ultra-speed, high security, and low power consumption. However, most transistor-type photonic memories developed to date still rely on electrical bias for operation, imposing certain limits on data transmission efficiency and energy consumption. In this study, the dual manipulation of "photo-writing" and "photo-erasing" of a novel photonic transistor memory is successfully realized by cleverly utilizing the complementary light absorption between the photoactive material, n-type BPE-PTCDI, in the active channel and the hybrid floating gate, CH3NH3PbBr3/poly(2-vinylpyridine). The fabricated device not only can be operated under the full spectrum but also shows stable switching cycles of photo-writing (PW)-reading (R)-photo-erasing (PE)-reading (R) (PW-R-PE-R) with a high memory ratio of ∼104, and the memory characteristics possess a stable long-term retention of >104 s. Notably, photo-erasing only requires 1 s light illumination. Due to the fully optical functionality, the rigid gate electrode is removed and a novel two-terminal flexible photonic memory is fabricated. The device not only exhibits stable electrical performance after 1000 bending cycles but also manifests a multilevel functional behavior, demonstrating a promising potential for the future development of photoactive electronic devices.