MECHANISMS OF MASS TRANSFER DURING ATOMIC OXYGEN RECOMBINATION ON METALLIC SEMICONDUCTORS

In order to show a correlation between the electronic properties of the semiconductors (energy gap band.) and their catalycity (activation of oxygen recombination reaction), we have studied the elementary phenomena of heat and mass transfers from a non equilibrium low pressure plasma of oxygen on an oxide semiconductor (n or p-type). In a pulsed radio frequency plasma reactor (13.56 MHz), mass transfer was evaluated by the measurement of recombination coefficient (Gamma) for nand p-type semiconductors having band gap energies varying from 0.3 to 7.3 eVe Results show a lower catalytic activity for n-type semiconductors than for the p-type ones. Moreover a correlation between the band gap energy and the oxide catalycity was observed for the p-type oxides: the activation energy of the recombination reaction depends linearly on the band gap energy.