The photocurrent-voltage characteristics and photoelectric sensitivity of a-Si:H samples with slit and comb electrodes are measured. A method for calculating the charge intensifying gain from the photoelectric sensiti...The photocurrent-voltage characteristics and photoelectric sensitivity of a-Si:H samples with slit and comb electrodes are measured. A method for calculating the charge intensifying gain from the photoelectric sensitivity is proposed. The obtained charge intensifying gain of a-Si:H under an electric field of 105 V/cm through this method is as high as 4.3×103. The generation process of the charge intensification effect in a-Si:H is discussed on the basis of the energy level diagram. And the product of electron’s mobility and its lifetime is calculated from the measured values of the gains.展开更多
Due to the difficulty in synthesizing perhalogenated metallophthalocyanine, the method of ammonium molybdate solid phase catalysis was introduced, and by using tetrachlorophthalic anhydride and urea as the raw materia...Due to the difficulty in synthesizing perhalogenated metallophthalocyanine, the method of ammonium molybdate solid phase catalysis was introduced, and by using tetrachlorophthalic anhydride and urea as the raw materials, hexadecachloro zinc phthalocyanine （ZnPcCl16） was synthesized. Components of the composite were analyzed by energy spectrum, and its functional group structures and absorption peaks were characterized by IR and UV-vis spectroscopy. The thin films of gas sensors were prepared in a vacuum evaporation system and evaporated onto SiO2 substrates, where sensing electrodes were made by MEMS micromachining. The optimal conditions for the films are： substrate temperature of 150 ℃ evaporation current of 95 A and film thickness of 50 nm. The result showed that the sensors were ideally sensitive to Cl2 gas and could detect the minimum concentration of 0.3 ppm.展开更多
The resistance-temperature properties of po- rous (Ba, Pb)TiO3 semiconductor ceramic were systemati- cally studied. It was found that the resistance of (Ba, Pb)TiO3 ceramic having been placed in the air for a long tim...The resistance-temperature properties of po- rous (Ba, Pb)TiO3 semiconductor ceramic were systemati- cally studied. It was found that the resistance of (Ba, Pb)TiO3 ceramic having been placed in the air for a long time was abnormally increased with the increase of the temperature from the room temperature to 70℃ prior to the Curie point. Further research showed that this abnormal resis- tance-temperature property was linked to its humidity sensi- tivity. When the relative humidity changed from 11% to 93%, the resistance of (Ba, Pb)TiO3 ceramic decreased three orders of magnitude. Furthermore, the humidity-resistance was approximately linear in single logarithm coordinate. According to the surface adsorption, grain-boundary poten- tial barrier and ferroelectric-paraelectric phase transforma- tion, the specific sensitive mechanism of (Ba, Pb)TiO3 ce- ramic was analyzed qualitatively.展开更多
文摘The photocurrent-voltage characteristics and photoelectric sensitivity of a-Si:H samples with slit and comb electrodes are measured. A method for calculating the charge intensifying gain from the photoelectric sensitivity is proposed. The obtained charge intensifying gain of a-Si:H under an electric field of 105 V/cm through this method is as high as 4.3×103. The generation process of the charge intensification effect in a-Si:H is discussed on the basis of the energy level diagram. And the product of electron’s mobility and its lifetime is calculated from the measured values of the gains.
基金supported by the National Natural Science Foundation of China (No. 60772019)the National High Technology Research andDevelopment program of China (No. 2006AA040101-05)the National Science Foundation for Post-Doctoral Scientists of China (No.20080440839).
文摘Due to the difficulty in synthesizing perhalogenated metallophthalocyanine, the method of ammonium molybdate solid phase catalysis was introduced, and by using tetrachlorophthalic anhydride and urea as the raw materials, hexadecachloro zinc phthalocyanine （ZnPcCl16） was synthesized. Components of the composite were analyzed by energy spectrum, and its functional group structures and absorption peaks were characterized by IR and UV-vis spectroscopy. The thin films of gas sensors were prepared in a vacuum evaporation system and evaporated onto SiO2 substrates, where sensing electrodes were made by MEMS micromachining. The optimal conditions for the films are： substrate temperature of 150 ℃ evaporation current of 95 A and film thickness of 50 nm. The result showed that the sensors were ideally sensitive to Cl2 gas and could detect the minimum concentration of 0.3 ppm.
基金This work was supported by the Key Problems Foundation of Shanxi Province(Grant No.021121)Youth Founda-tion of Taiyuan University of Technology(Grant No.190-12901073).
文摘The resistance-temperature properties of po- rous (Ba, Pb)TiO3 semiconductor ceramic were systemati- cally studied. It was found that the resistance of (Ba, Pb)TiO3 ceramic having been placed in the air for a long time was abnormally increased with the increase of the temperature from the room temperature to 70℃ prior to the Curie point. Further research showed that this abnormal resis- tance-temperature property was linked to its humidity sensi- tivity. When the relative humidity changed from 11% to 93%, the resistance of (Ba, Pb)TiO3 ceramic decreased three orders of magnitude. Furthermore, the humidity-resistance was approximately linear in single logarithm coordinate. According to the surface adsorption, grain-boundary poten- tial barrier and ferroelectric-paraelectric phase transforma- tion, the specific sensitive mechanism of (Ba, Pb)TiO3 ce- ramic was analyzed qualitatively.
