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• In the process of CVD growth, the concentration of reactants in the substrate region was increased by the method of space compression, the number of nucleation was effectively controlled, and larger size (∼50 µm) Bi 2 O 2 Se was obtained. • Based on the influence of different temperature on the growth of Bi 2 O 2 Se, the nucleation and selenization mechanism of Bi 2 O 3 were revealed, and the controllable growth of Bi 2 O 2 Se in a certain thickness range was realized. • A two-end photodetector was constructed based on Bi 2 O 2 Se with high crystallinity. The device exhibits a response of up to 9550A/W under 405 nm laser excitation. Bi 2 O 2 Se has attracted a lot of attention in the field of photodetection due to its ultra-high mobility and tunable band gap. However, the mechanism of controllable preparation of high-quality Bi 2 O 2 Se is unclear and needs further investigation. In this paper, the concentration of reactants in the substrate region was increased by the method of space-compression, the number of nucleation was effectively controlled, and larger size Bi 2 O 2 Se was obtained. And the nucleation and selenylation mechanisms of Bi 2 O 3 were revealed based on the effect of temperatures modificatives growth of Bi 2 O 2 Se. And the controlled growth was achieved in a certain thickness range by increasing the reactant concentration in the substrate region and controlling the nucleation number. Moreover, photodetectors were constructed based on the highly crystalline Bi 2 O 2 Se. The photodetector exhibited a photoresponsivity of up to 9550 A/W under the excitation of 405 nm light and obtained highly stable and recoverable characteristics with multiple laser switches. [ABSTRACT FROM AUTHOR]

[Display omitted] • A nociceptor model based memristor was developed and optimized for simulating bionic characteristics. • The artificial nociceptor based ITO/TiOx/TiN memristor was fabricated and used to emulate for human sensory system. • TiOx-based memristor device shows excellent nociceptive characteristics including threshold, allodynia, and hyperalgesia. Memristors are expected to be further applied in artificial intelligence due to their simple structure and similarity to biological synapses. A model based memristor is developed and optimized to realize an artificial nociceptor, a special receptor that responds to an external stimulus and produces biochemical signals in the body according to the intensity, duration, and number of repetitions of the stimulus. Then the memristors with an ITO/TiO x /TiN structure are presented to imitate nociceptive behaviors including threshold, relaxation, no adaptation, allodynia, and hyperalgesia. The results show that the memristor device we fabricated has a well correspondence with the memristor model. With its excellent synaptic properties and good biocompatibility, TiO 2 is expected to show more potential in the fields of artificial intelligence such as electronic skin and humanoid robot. [ABSTRACT FROM AUTHOR]

• Controllable synthesis of WS 2 films with monolayer, bilayer and tri-layer. • The growth mechanism is proposed based on the analysis of the relationship between the mass transfer rate and the chemical reaction rate of the reactants. • Electrical properties of WS 2 with different layers. Two-dimensional tungsten disulfide (WS 2) has been widely studied owing to its superior optical and electrical properties. Since the growth mechanism is unclear, controllable synthesis of 2D WS 2 is still a challenge. Based on the analysis of the relationship between the mass transfer rate and the chemical reaction rate of the reactants, we control the lateral and longitudinal growth of the films by regulating the Ar flow rate in the growth stage, and then realize the controllable synthesis of WS 2 films with monolayer, bilayer and tri-layer. In addition, back-gated FETs were fabricated based on WS 2 thin films with different layers. Monolayer WS 2 showed n-type characteristics with a carrier mobility of ~1.5 cm2 V−1 s−1, whereas bilayer WS 2 showed a higher mobility of ~13 cm2 V−1 s−1 with the I on /I off ratio of ~106. Our work paves the way for the development of next generation photoelectronic devices based on 2D materials. [ABSTRACT FROM AUTHOR]