Abstract: A method of fabricating a halide perovskite having a general formula of ABX3, wherein A, B, and X are inorganic elements and X is a halide, the method including a vapor-liquid-solid process triggered by a catalyst formed from a noble metal; A nanowire of the halide perovskite and a photoelectronic device thereof.

Abstract: Inorganic semiconductors typically have limited p-type behavior due to the scarcity of holes and the localized valence band maximum, hindering the progress of complementary devices and circuits. In this work, we propose an inorganic blending strategy to activate the hole-transporting character in an inorganic semiconductor compound, namely tellurium-selenium-oxygen (TeSeO). By rationally combining intrinsic p-type semimetal, semiconductor, and wide-bandgap semiconductor into a single compound, the TeSeO system displays tunable bandgaps ranging from 0.7 to 2.2 eV. Wafer-scale ultrathin TeSeO films, which can be deposited at room temperature, display high hole field-effect mobility of 48.5 cm2/(Vs) and robust hole transport properties, facilitated by Te—Te (Se) portions and O—Te—O portions, respectively.

Abstract: Visible and infrared radiation photothermoelectric effect photodetectors are provided. The photodetectors are formed on substrates having a low thermal diffusivity of less than 0.05 mm2/sec. A thermoelectric metal chalcogenide film is formed on the low thermal diffusivity substrate. At least two symmetric electrodes are formed on the thermoelectric metal chalcogenide film such that the thermoelectric metal chalcogenide film forms a channel between the electrodes. The photodetector has a responsivity of at least approximately 65 V W?1 for 1550 nm illumination and a response time less than approximately ˜60 ms. The photodetector photoresponse is tunable via manipulation of local illumination. Examples of photodetectors use Bi2Se3, Bi2Te3, and SnSe2 on flexible polymeric substrates. By using large-area thermoelectric films with a photothermal detection mechanism, and modulating responsivity via thermal coupling, photodetector arrays for wearable electronics and integrated optoelectronic circuits may be created.

Abstract: A method of fabricating semiconducting tellurium (Te) nanomesh. The method includes the steps of preparing a substrate, vaporizing Te powders under a first temperature; and growing Te nanomesh on the substrate using the vaporized Te powders under a second temperature. The first temperature is higher than the second temperature. The rationally designed nanomesh exhibits exciting properties, such as micrometer-level patterning capacity, excellent field-effect hole mobility, fast photoresponse in the optical communication region, and controllable electronic structure of the mixed-dimensional heterojunctions.

Abstract: The large-scale artificial synaptic device arrays based on the organic molecule-nanowire heterojunctions with tunable photoconductivity are proposed and demonstrated. The organic thin films of p-type 2,7-dioctyl[1]benzothieno[3,2-b][1] benzothiophene (C8-BTBT) or n-type phenyl-C61-butyric acid methyl ester (PC61BM) are used to wrap the InGaAs nanowire parallel arrays to configure two different type-I heterojunctions, respectively. Due to the difference in carrier injection, persistent negative photoconductivity (NPC) or positive photoconductivity (PPC) are achieved in these heterojunctions. The irradiation with different wavelengths (solar-blind to visible ranges) can stimulate the heterojunction devices, effectively mimicking the synaptic behaviors with two different photoconductivities. Evidently, these photosynaptic devices are illustrated with retina-like behaviors and capabilities for large-area integration, which reveals their promising potential for artificial visual systems.

Abstract: A method of forming a bismuth chalcogenide film is disclosed including the steps of (a) forming at least one bismuth (Bi) elemental layer on a substrate, (b) forming at least one selenium (Se) or tellurium (Te) elemental layer on the substrate, and (c) after steps (a) and (b), heating the substrate to form a bismuth chalcogenide film.

Abstract: A method of fabricating a halide perovskite having a general formula of ABX3, wherein A, B, and X are inorganic elements and X is a halide, the method including a vapor-liquid-solid process triggered by a catalyst formed from a halide precursor of inorganic element B. A ABX3 nanowire formed by the method and a photoelectronic device with the ABX3 nanowire.

Abstract: The surface of low-dimensional perovskites plays a crucial role in determining their intrinsic properties. Thus, specific surfaces may be designed to obtain a desired characteristic and/or a functional structure. Further, surface passivation could also be applied to stabilize and optimize the state-of-the-art perovskite-based optoelectronics. CsPbBr3 microwires parallel arrays with specific (100)-terminated crystal planes were designed and fabricated to have excellent photodetection performance with long-term environment stability over 3000 hours. Further, environmental oxygen may be used to passivate the Br-vacancy-related trap states on the (100) surface and to create charge carrier nanochannels to enhance the (opto)electronic properties. The coupling effects between oxygen species and the specific terminated crystal planes of perovskites highlight the importance of surface engineering for designing and optimizing perovskite-based devices.

Abstract: In this invention, a high-performance photodetector based on 2D bilayered hybrid lead halide perovskite single crystal with ACI phase, with a chemical formula of GAMA2Pb2I7 where GA is C(NH2)3 and MA is CH3NH3,) was fabricated, using a facile and cost-effective method based on cooling crystallization. The single-crystal photodetector exhibits high photoresponsivity, together with correspondingly high detectivity values. Meanwhile, a high-resolution imaging sensor is built based on the GAMA2Pb2I7 single-crystal photodetector, confirming the high stability and photosensitivity of the imaging system.

Abstract: Visible and infrared radiation photothermoelectric effect photodetectors are provided. The photodetectors are formed on substrates having a low thermal diffusivity of less than 0.05 mm2/sec. A thermoelectric metal chalcogenide film is formed on the low thermal diffusivity substrate. At least two symmetric electrodes are formed on the thermoelectric metal chalcogenide film such that the thermoelectric metal chalcogenide film forms a channel between the electrodes. The photodetector has a responsivity of at least approximately 65 V W?1 for 1550 nm illumination and a response time less than approximately ˜60 ms. The photodetector photoresponse is tunable via manipulation of local illumination. Examples of photodetectors use Bi2Se3, Bi2Te3, and SnSe2 on flexible polymeric substrates. By using large-area thermoelectric films with a photothermal detection mechanism, and modulating responsivity via thermal coupling, photodetector arrays for wearable electronics and integrated optoelectronic circuits may be created.

Abstract: Continuous miniaturization of semiconductor devices is the key to boosting modern electronics development. However, such downscaling strategy has been rarely utilized in photoelectronics and photovoltaics. Here, in this work, a full-vdWs 1D p-Te/2D n-Bi2O2Se heterodiode with a rationally-designed nanoscale ultra-photosensitive channel is reported. Enabled by the dangling bond-free mixed-dimensional vdWs integration, the Te/Bi2O2Se type-II diodes show a high rectification ratio of 3.6×104. Operating with 100 mV reverse bias or in a self-power mode, the photodiodes demonstrated excellent photodetection performances, including high responsivities of 130 A W?1 (100 mV bias) and 768.8 mA W?1 (self-power mode), surpassing most of the reports of other heterostructures. More importantly, a superlinear photoelectric conversion phenomenon is uncovered in these nanoscale full-vdWs photodiodes, in which a model based on the in-gap trap-assisted recombination is proposed for this superlinearity.

Abstract: Mixed-dimensional heterostructure nano-devices with multi-functionality for use in semiconductors. Specifically, a gate-tunable and anti-ambipolar phototransistor is devised based on 1D p-type GaAsSb nanowire/2D n-type MoS2 nanoflake mixed-dimensional van der Waals (vdW) heterojunctions. Methods of making the mixed-dimensional heterostructure nano-devices with multi-functionality, gate-tunability and anti-ambipolar phototransistor.

Abstract: A method of fabricating a halide perovskite having a general formula of ABX3, wherein A, B, and X are inorganic elements and X is a halide, the method including a vapor-liquid-solid process triggered by a catalyst formed from a halide precursor of inorganic element B. A ABX3 nanowire formed by the method and a photoelectronic device with the ABX3 nanowire.

Abstract: A method of fabricating a halide perovskite having a general formula of ABX3, wherein A, B, and X are inorganic elements and X is a halide, the method including a vapor-liquid-solid process triggered by a catalyst formed from a noble metal; A nanowire of the halide perovskite and a photoelectronic device thereof

Abstract: The large-scale artificial synaptic device arrays based on the organic molecule-nanowire heterojunctions with tunable photoconductivity are proposed and demonstrated. The organic thin films of p-type 2,7-dioctyl[1]benzothieno[3,2-b][1] benzothiophene (C8-BTBT) or n-type phenyl-C61-butyric acid methyl ester (PC61BM) are used to wrap the InGaAs nanowire parallel arrays to configure two different type-I heterojunctions, respectively. Due to the difference in carrier injection, persistent negative photoconductivity (NPC) or positive photoconductivity (PPC) are achieved in these heterojunctions. The irradiation with different wavelengths (solar-blind to visible ranges) can stimulate the heterojunction devices, effectively mimicking the synaptic behaviors with two different photoconductivities. Evidently, these photosynaptic devices are illustrated with retina-like behaviors and capabilities for large-area integration, which reveals their promising potential for artificial visual systems.

Abstract: A method of fabricating semiconducting tellurium (Te) nanomesh. The method includes the steps of preparing a substrate, vaporizing Te powders under a first temperature; and growing Te nanomesh on the substrate using the vaporized Te powders under a second temperature. The first temperature is higher than the second temperature. The rationally designed nanomesh exhibits exciting properties, such as micrometer-level patterning capacity, excellent field-effect hole mobility, fast photoresponse in the optical communication region, and controllable electronic structure of the mixed-dimensional heterojunctions.