Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Palladium nanoparticles on InP for hydrogen detection | Cernohorsky et al. Nanoscale Research Letters 2011 6 410 http content 6 1 410 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Palladium nanoparticles on InP for hydrogen detection 2 2 2 1 Ondrej Cernohorsky Karel Zdansky Jiri Zavadil Pavel Kacerovsky and Katerina Piksova Abstract Layers of palladium Pd nanoparticles on indium phosphide InP were prepared by electrophoretic deposition from the colloid solution of Pd nanoparticles. Layers prepared by an opposite polarity of deposition showed different physical and morphological properties. Particles in solution are separated and after deposition onto the InP surface they form small aggregates. The size of the aggregates is dependent on the time of deposition. If the aggregates are small the layer has no lateral conductance. Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height. The response of the structure on the presence of hydrogen was monitored. Introduction An energetic barrier called the Schottky barrier is formed on the interface of a metal and semiconductor. This barrier shows a rectifying effect like classical PN diodes. This structure could be exploited as a hydrogen sensor where the sensing mechanism consists in the change of the barrier height by the presence of hydrogen on the interface. A palladium Pd was used here for its ability to dissociate hydrogen molecules to single atoms. This fact is further enhanced by the nanoparticle form of Pd because of its high surface-to-volume ratio. An n-type indium phosphide InP played the role of the semiconductor here. Electrophoretic deposition of Pd nanoparticles from their colloid solution appeared to be the most convenient method for the interface preparation in the sense of the Schottky barrier height and therefore also for the sensitivity of the sensor 1 . The Schottky barrier height FB is theoretically given in the case of n-type semiconductors by
