Comprehensive study of adsorption kinetics for hydrogen sensing with an electroless-plated Pd–InP Schottky diode

On a Schottky diode-type hydrogen sensor with pyramid-like Pd nanostructures

“…From the slope and intercept of this plot, the change of enthalpy (DH ) and the change of entropy (DS ) values of the device A are À31.86 kJ mol À1 and À66.18 J mol À1 K À1 , respectively. The negative DH confirms the exothermic reaction of this hydrogen adsorption process [26], which reveals lower hydrogen coverage at higher temperature. On the other hand, the negative DS reflects the reduction of randomness.…”

“…On the other hand, the negative DS reflects the reduction of randomness. This represents that hydrogen atoms adsorbed in the state of a Pd/AlGaN interfacial dipolar layer are more ordered than those in the gas state [26].…”

“…For the studied Schottky diode-type hydrogen gas sensor, the adsorption reaction could be expressed as [26]:…”

Pt Schottky diode gas sensors formed on GaN and AlGaN/GaN heterostructure

“…Then, the observed on-off symmetry can be explained by assuming that the adsorption process is a chemisorption process accompanying a reduction of the chemical potential for H atoms similarly to the models proposed by other groups for Pd/SiO 2 /Si and Pd/n-InP interfaces [11,12]. Then, desorption requires thermal energy supply, leading to a longer recovery time than adsorption.…”

High temperature sensing characteristics of a high performance Pd/AlGaN/GaN Schottky diode hydrogen sensor obtained by oxygen gettering

“…Performances of the present sensor are compared in Table 1 in terms of ∆φ Bmax with those of GaAs and InP Schottky diode sensors reported in literature [10,11]. It is seen that the present sensor gives the superior performance over others.…”