The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecul...The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm-1 for Mo2N/Al2O3 catalyst, 2054 cm-1 for MozC/Al2O3 catalyst and 2037 cm-1 for MoP/Al2O3 catalyst, respectively. A strong band at 2200 cm-1 for Mo2N/Al2O3 catalyst, which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms, and a weak band at 2196 cm-1 for Mo2C/Al2O3 catalyst, which could be attributed to CCO species, were also detected. CO adsorbed on fresh Mo2N/Al2O3 catalyst, Mo2C/Al2O3 catalyst and MoP/Al2O3 catalyst, showed strong molecular adsorption, just like noble metals. Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo2N/Al2O3, Mo2C/Al2O3 and MoP/Al2O3 catalysts and noble metals.展开更多
We report Al0.30Ga0.70N//GaN/Al0.07Ga0.93N double heterostructure high electron mobility transistors with a record saturation drain current of 1050mA/mm. By optimizing the graded buffer layer and the GaN channel thick...We report Al0.30Ga0.70N//GaN/Al0.07Ga0.93N double heterostructure high electron mobility transistors with a record saturation drain current of 1050mA/mm. By optimizing the graded buffer layer and the GaN channel thickness, both the crystal quality and the device performance are improved signiflcantly, including electron mobility promoted from 1535 to 1602 cm2//V.s, sheet carrier density improved from 0.87× 10^13 to 1.15× 10^13 cm^-2, edge dislocation density reduced from 2.5× 10^10 to 1.3× 10^9 cm^ -2, saturation drain current promoted from 757 to record 1050mA/mm, mesa lealmge reduced by two orders in magnitude, and breakdown voltage promoted from 72 to 108 V.展开更多
基金supported by the National Nature Science Foundation of China(No.20903054).
文摘The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm-1 for Mo2N/Al2O3 catalyst, 2054 cm-1 for MozC/Al2O3 catalyst and 2037 cm-1 for MoP/Al2O3 catalyst, respectively. A strong band at 2200 cm-1 for Mo2N/Al2O3 catalyst, which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms, and a weak band at 2196 cm-1 for Mo2C/Al2O3 catalyst, which could be attributed to CCO species, were also detected. CO adsorbed on fresh Mo2N/Al2O3 catalyst, Mo2C/Al2O3 catalyst and MoP/Al2O3 catalyst, showed strong molecular adsorption, just like noble metals. Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo2N/Al2O3, Mo2C/Al2O3 and MoP/Al2O3 catalysts and noble metals.
基金Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02308-002the National Natural Science Foundation of China under Grant Nos 11435010 and 61474086
文摘We report Al0.30Ga0.70N//GaN/Al0.07Ga0.93N double heterostructure high electron mobility transistors with a record saturation drain current of 1050mA/mm. By optimizing the graded buffer layer and the GaN channel thickness, both the crystal quality and the device performance are improved signiflcantly, including electron mobility promoted from 1535 to 1602 cm2//V.s, sheet carrier density improved from 0.87× 10^13 to 1.15× 10^13 cm^-2, edge dislocation density reduced from 2.5× 10^10 to 1.3× 10^9 cm^ -2, saturation drain current promoted from 757 to record 1050mA/mm, mesa lealmge reduced by two orders in magnitude, and breakdown voltage promoted from 72 to 108 V.
基金Project(20092302120056)supported by Specialized Research Fund for the Doctoral Program of Higher Education of China(SRFDP)Project(LBH-Z08160)supported by Heilongjiang Postdoctoral Grant,China
