Humidity-voltaic characteristics of Au–porous silicon interfaces

• Published in: Journal of physics. D, Applied physics Vol. 37; no. 3; pp. 404 - 408
• Main Authors: Dzhafarov, T D, Oruc, C, Aydin, S
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 07.02.2004; Institute of Physics
• Subjects: Catalysis; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Porous materials; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Relative humidity; Gold; Humidity effect; Voltage; Transition metal; Silicon; Diffusion coefficient; Diffusion; Hydrogen ion; Porous material; Catalyst; Interface
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/37/3/016

The humidity-voltaic effect, i.e., generation of open-circuit voltage, V(sub oc), in Au-porous silicon (PS) interface in humid atmosphere (up to 450 mV at 95 percent relative humidity) in dark and daylight illumination is discovered. The humidity-stimulated voltage generation is attributed to the splitting of water and hydrogen molecules on the surfaces of the Au catalyst, where further diffusion penetration of hydrogen ions into the Au-PS interface results in the formation of dipoles, thus inducing V(sub oc) across dipoles. The generation of V(sub oc) (up to 550 mV) has also been observed on dipping of Au-PS structures in different hydrogen-containing solutions (ethanol, benzine, sodium tetraborate pentahydrate, etc). Data of response time-dependent changes of the open-circuit voltage generated in Au-PS structures under humid conditions were used for the estimation of diffusion coefficients of hydrogen. The temperature dependence of the diffusion coefficient of hydrogen at 323-353 K via the pore surfaces of PS is attributed to be D = 1.3 x 10 exp -2 exp(-0.25/kT).