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In this letter, we propose that the narrowband photodetection can be realized in the skin layer of semiconductors with the spatially separated photo-excited carriers from the nanoscale heterolattice electronic transitions (NanoHLETs). The NanoHLET photodetection is demonstrated by measuring the photoconductive responses of the $\sim$ 1 $\mu$m thick films of TiO$_{2}$ glass embedded with rutile and anatase TiO$_{2}$ nanocrystals. As containing only rutile nanocrystals, the TiO$_{2}$ glass film presents the responsivity curve with only one sharp peak centered at 423.0 nm with a full-width-at-half-maximum (FWHM) of 13.7 nm. This NanoHLET mechanism may open a new way in making ultra-small narrow-band photodetectors matching the current nanoscale electronic technology.

Artificial feeding is still widely used by small and medium-sized farmers in aquaculture, which requires a large labor cost and cannot guarantee the feeding efficiency. A mobile, low-cost, simple and practical feeding device for aquaculture feed was designed, including the overall scheme, the design of silo, feeding bucket, feeding mechanism and other mechanical structures. The feeding device can reduce the cost of aquaculture and improve the feeding efficiency.

In order to know aquaculture water quality situations in the real time, ease work strength of aquaculture workers, and improve aquaculture efficiency, this paper develops the remote monitoring system for aquaculture water quality based on Internet of Things, including selection of water quality monitoring parameters, overall design of monitoring system, type selection of single chip microcontroller and sensor, design of monitoring system software, and water quality parameter sampling design. The aquaculture workers could understand information of aquaculture water body such as dissolved oxygen concentration, pH value, ammonia-nitrogen content, and temperature through remote monitoring system, and remotely control the aquaculture water quality for targeted purpose.

Gallium arsenide (GaAs) nanowires are epitaxially grown on an N-type Si (111) substrate by molecular beam epitaxy according to self-catalysis growth mechanism. Testing the grown nanowires by scanning electron microscope, it is found that the nanowires have high verticality and good uniformity in length and diameter. Variable temperature photoluminescence (PL) spectroscopy is used on nanowires. The test results show that the two luminescence peaks P1 and P2 at 10 K are located at 1.493 eV and 1.516 eV, respectively, and it is inferred that it may be the luminescence caused by WZ/ZB miscible structure and the free exciton luminescence peak. These two peaks present red-shift with temperature increasing. The temperature change curve is obtained by fitting the Varshni formula. The variable power PL spectroscopy test finds that the peak position of P1 position is blue shifted with power increasing, but the peak position of the P2 remains unchanged. By fitting, it is found that the P1 peak position is linearly related to power to the power of 1/3, and it is judged that it may be type-II luminescence caused by WZ/ZB mixed phase structure. At the same time, the peak position of the P2 position is fitted and parameter α approximately equals 1.56, therefore P2 is a free exciton luminescence. A Raman spectrum test is performed on the nanowires, and an E2 phonon peak unique to the GaAs WZ structure is found from the spectrum. It is proved that the grown nanowires possess WZ/ZB mixed phase structures, and the hybrid phase structure of nanowires is more intuitively observed by high resolution transmission electron microscopy.

Indium tin oxide (ITO) thin films,as a heavy doping n-type semiconductor material with a high carrier concentration,can realize the surface plasma effect and regulation of surface plasmon resonance wavelength in the near infrared region:the surface plasma has broad application prospect in surface plasmon devices.The ITO thin films are deposited on float glass substrates (20 mm20 mm) via the direct current (DC) magnetron sputtering by regulating substrate temperature from 100 ℃ to 500 ℃.The deposited ITO thin films present a cubic polycrystalline iron manganese structure,in which the ITO film shows the strong crystallinity at 400 ℃,so that it is conducive to reducing the defects of bound electrons and the damping force of thin film.The surface roughness of ITO thin film first decreases and then increases with the temperature increasing,correspondingly the root-mean-square roughness (Rq) of these films decreases from 4.11~nm to 2.19 nm,then increases to 2.56 nm.The Rqvalue of 2.19 nm corresponds to a preferable surface smoothness of ITO thin film,indicating that it can effectively increase carrier concentration of ITO thin film at 400 ℃.The effects of the different substrate temperature on the photoelectric and surface plasma properties of ITO thin films are analyzed by UV-Vis absorption spectra,Hall measurement,refractive index and dielectric constant.As the temperature increases from 100 ℃ to 500 ℃,the carrier concentration of ITO thin film is enhanced from 4.11020 cm-3 to 2.481021 cm-3,and thus increasing the probability of the Fermi level to the conduction band of ITO thin film.And the enhancement of carrier concentration induces the Moss-Burstein effect,which makes the edges of absorption spectrum of the ITO thin film gradually blue-shift from 340 nm to 312 nm,correspondingly broadening the optical band gap from 3.64 eV to 3.97 eV.These results cause the difficulties of electrons interband transition to be enhanced,and thus suppressing the phenomenon of absorbing photons for the electron transition from low level to high level,which ultimately reduces the optical loss of ITO thin film.In addition,the surface plasma effect is realized in a range from 1100 nm to 1700 nm for ITO thin film by regulating the substrate temperature.Meanwhile,the electronic mobility in the ITO thin film is also improved from 24.6 cm2V-1s-1 to 32.2 cm2V-1s-1,which reduces the electronic scattering,and is beneficial to the increase of propagation length of surface plasma waves.The above results imply that we have attained the goal of the reducing the electrical loss of ITO thin film.