Currently, Nanjing South Railway Stationplanning to implement slate roof renovation is integratingsolar cell modules into traditional roof materials to generateclean energy. Copper–indium–gallium diselenide（CuIn1-xGaxSe2, CIGS） is one of the most promisingmaterials for thin film solar cells. Cu（In1-xGax）Se2 filmswere deposited by a one-step radio frequency magnetronsputtering process at low substrate temperature. X-raydiffraction, Raman, scanning electron microscopy, energydispersiveX-ray spectroscopy, and electrical and opticalmeasurements were carried out to investigate the depositedfilms. The results reveal that a temperature of 320 C iscritical for near-stoichiometric CIGS films with uniformsurface morphology. Cu-rich phase particulates are foundat less than this temperature. The sample deposited at380 C gives well-crystalline single-phase CIGS film.Furthermore, the electrical and optical performances of theabsorber layer are improved significantly with theincreasing substrate temperature.
Perovskite-based materials can be widely used in the aerospace and transportation field. Perovskite man-ganese oxides La0.7Sr0.3MnO3 （LSMO） thin films were grown on LaAlO3 （100） and Si （100） single crystal sub-strates by the polymer-assisted chemical solution deposi-tion （PACSD） method. Electronic transport behavior, microstructure, and magnetoresistance （MR） of LSMO thin films on different substrates were investigated. The resis-tance of LSMO films fabricated on LaAlO3 substrates is smaller than that on the Si substrates. The magnetic field reduces resistance of LSMO films both on Si and LAO in the wide temperature region, when the insulator-metal transition temperature shifts to higher temperature. The low-field magnetoresistance of LSMO films on Si in low temperature range at 1 T is larger than that of LSMO films on LAO. However, the MR of LSMO film on LAO films at room-temperature is about 5.17%. The thin films are smooth and dense with uniform nanocrystal size grain. These results demonstrate that PACSD is an effective technique for producing high quality LSMO films, which is significant to improve the magnetic properties and the application of automotive sensor.
Topological insulators are insulating in the bulkbut have metallic surface states. Its unique physicochemicalproperties can find numerous applications in electronics,spintronics, photonics, the energy sciences, and thesignal control of transportation. We report an experimentalapproach to synthesize the high-quality single crystal oftopological insulator Bi2Te3 by using self-flux method. Weobtained the optimal preparation conditions by adjustingthe parameters of heat treatment, and successfully preparedthe single-crystal Bi2Te3 sample. The as-grown sampleshave a surface with bright metallic luster and are soft andfragile. Furthermore, Bi2Te3 has the obvious layer structurefrom SEM results. The data of X-ray diffraction andscanning electron microscope show that Bi2Te3 singlecrystal grows along the c-axis with the order of Te（1）–Bi–Te（2）–Bi–Te（1） and crystallizes in the hexagonal systemwith space group of R/3 m. The q–T curve shows that qdecreases with temperature, showing metallic behaviorover the whole temperature range.
Magnetoresistive sensor can be widely used in modem transportation field, such as the vehicle positioning and navigation system, vehicle detection system, and intelligent transportation system. In order to improve the efficiency of magnetoresistive sensor, we synthesized Lao.sSro.2MnO3 polycrystalline bulks at different sintering temperatures and investigated their DC and AC transport properties in this work. As a result, all samples showed insulator-metal （I-M） phase transition, and the transition temperature （TI-M） shifted to higher temperature with the increase of sintering temperature. The TI-M measured at different AC frequencies was smaller than that measured at DC condition, which implied that the I-M phase transition was suppressed at AC frequencies. The resistivity mea- sured at high AC frequencies was larger than that measured at low AC frequencies, which could be attributed to the change of the magnetic penetration depth （6）. However, the room-temperature AC-magnetoresistance （MR） at low frequencies was much larger than that at high frequencies and room-temperature DC-MR. These findings demon- strate that reducing the AC frequency is an effective way for enhancing the room-temperature MR, which can be used to promote the efficiency of magnetoresistive sensor.
