ELECTROPHORETIC DEPOSITION OF PALLADIUM NANOPARTICLES ON InP FOR HYDROGEN SENSORS

Semiconducting, insulating, and metallic nanoparticles have attracted considerable interest due to their size-dependent, quantum confinement characteristics, which make them attractive for a wide range of optical, magnetic, and electronic devices. We report on the deposition of Pd nanoparticles prepared with reverse micellae of water/AOT/isooctane solution on the surface of n-type InP substrates and epitaxial layers. High quality metal/InP interfaces are essential for the fabrication of high-speed electronic devices, charge-control devices, optoelectronic and particle detectors. Thanks to catalytic activity of Pd, increasing number of papers has been devoted to hydrogen sensors based on Pd/InP interfaces [1]. Sensors based on Schottky diodes are capable of monitoring hydrogen and hydrogen-containing moieties in subppm and ppm range [2]. The hydrogen molecules are absorbed and dissociated at Pd surface, atomic hydrogen rapidly diffuses to the Pd/InP interface, where the dipole layer develops. Subsequently, the Schottky barrier height decreases and the electric current increases.