Corrosion and corrosion suppression on n-type gallium arsenide semiconductor liquid-junction solar cells

N-type GaAs is a potentially useful semiconductor in liquid junction type solar cells. Corrosion and corrosion suppression on an n-type GaAs semiconductor in both light and dark has been studied. The application of non-electroactive layers for corrosion suppression on semiconductor electrodes is a relatively new field. GaAs corrodes to form Ga(III) and As(III) solution species during photocurrent generation. The corrosion rate is determined electroanalytically in acidic media by measuring As(III) using differential pulse polarography (DPP). In neutral electrolytes a rotating ring-disc experiment measured the efficiency of hole-transfer to a redox couple. Two protecting processes have been utilized. Silanization and electrochemical polymerization of divinylbenzene and phenol were used to deposit non-electroactive layers on the electrode surface. The polyphenylene oxide coating partially suppressed corrosion in acid electrolytes. However, the coatings did not improve hole transfer efficiency in neutral electrolytes.