DISPLACEMENT OF THE BANDEDGES OF GALNP(2) IN AQUEOUS-ELECTROLYTES INDUCED BY SURFACE MODIFICATION

The surface of epi layer p-GaInP2 electrodes was treated using 8-quino linol, cupferron, and ferrocyanide, producing a modified surface direc ted at varying the Helmholtz layer charge. Mott-Schottky and photocurr ent-voltage measurements were carried out to determine if there was an y shift in the flatband potential or change in the onset of photocurre nt due to the altered surface charge. Treatments with 8-quinolinol and cupferron were found to shift the flatband to more positive potential s; treatments with ferrocyanide produced a negative shift. The quinola te-modified interface had flatband potentials that were pH independent in the range 5 through 8. Photoluminescence studies on electrodes tha t were etched, treated with 8-quinolinol, and exposed to air for long periods showed no degradation of the luminescence intensity or photolu minescence decay time, in contrast to untreated electrodes.