Shuo Chen,Xuemei Liu,Xvsheng Qiao,Xia Wan,Khurram Shehzad,Xianghua Zhang,Yang Xu,Xianping Fan
An effective colloidal process involving the hot-injection method is developed to synthesize uniform nanoflowers consisting of 2D γ-In 2 Se 3 nanosheets. By exploiting the narrow direct bandgap and high absorption coefficient in the visible light range of In 2 Se 3 , a high-quality γ-In 2 Se 3 /Si heterojunction photodiode is fabricated. This photodiode shows a high photoresponse under light illumination, short response/recovery times, and long-term durability. In addition, the γ-In 2 Se 3 /Si heterojunction photodiode is self-powered and displays a broadband spectral response ranging from UV to IR with a high responsivity and detectivity. These excellent performances make the γ-In 2 Se 3 /Si heterojunction very interesting as highly efficient photodetectors.
Haixia Xing,Xinlei Li,Shupeng Sun,Baoyu Huang,Xiaogan Li
The γ-In 2 Se 3 /In 2 O 3 nanoflower-like heterojunctions were synthesized by solvothermal treatment followed by thermal oxidation in Air. The nanoflower-like γ-In 2 Se 3 /In 2 O 3 -based chemiresistive-type sensor showed a significantly enhanced response to NO 2 at an operating temperature of 170°C. The sensor achieves a response of 2.69–0.2 ppm NO 2 at 170°C. The sensor exhibits remarkable selectivity to several possible interferents such as carbon monoxide , ammonia, formaldehyde, acetone, methanol, and toluene, and good stability at 170°C. The nanoflower structure increases the specific surface area and introduces more active sites, which improves the sensitivity of the sensor to NO 2 . The heterojunction formed between γ-In 2 Se 3 and In 2 O 3 improves the charge carrier transfer between NO 2 gas molecules and sensing materials, thereby increasing the response of the sensor to NO 2 . Density functional theory was used to elucidate this sensing mechanism, and it was found that improved sensing performance is mainly due to heterojunction formation , which increases the adsorption energy of nitrogen dioxide molecules on a sensing material surface and facilitates charge transfer between molecules.
Makkawi Osman,Yanmin Huang,Wei Feng,Guangbo Liu,Yunfeng Qiu,PingAn Hu
Phase engineering of two-dimensional (2D) materials offers unique opportunities for acquiring novel opto-electronic properties and allows for the searching of outstanding candidates for applications in opto-electronic detectors, sensors, catalysis, or phase-change memory devices. Here, we report the phase-transformation from β-InSe to γ-In2Se3, exploiting the thermal annealing route to trigger the process starting at 200 °C that expands the family of phase-change materials. The presence of γ-In2Se3 is solidly confirmed by the characteristic peaks in X-ray diffraction (XRD) and energy dispersive X-ray (EDX), and is quite stable at ambient condition, thus facilitating substantial application in phase-change memory devices. A Raman shift in the A′1 mode from 225 cm−1 to 230 cm−1 further illustrates the phase transformation. Besides the photoluminescence (PL) peak of β-InSe, the ∼2 eV PL peak, ascribed to γ-In2Se3, is observed in the annealed nanosheet. The increased PL band gap of β-InSe as a function of annealing temperature during phase transformation was possibly affected by the suppressed interlayer coupling, as well as the planar quantum confinement of photo-excited carriers by the external surfaces of the sheets. The photodetector performance with respect to photocurrent, mobility, detectivity, responsivity, and external quantum efficiency was subsequently evaluated after thermal annealing, showing deteriorated optical performance. The present work proved that thermal annealing could induce the successful phase transformation, and adjusted the opto-electronic properties in some extent, providing useful information for processing 2D materials based nano-devices.
危险品化学品经营许可证（带存储）