CONTROLLING THE WORK FUNCTION OF CDSE BY CHEMISORPTION OF BENZOIC-ACID DERIVATIVES AND CHEMICAL ETCHING

Fourier transform infrared spectroscopy shows that benzoic acid and it s derivatives can bind chemically to the surfaces of CdSe. The dipole moment of the adsorbed benzoate correlates linearly with changes in th e semiconductor work function, as determined by vibrating capacitor (K elvin probe) measurements. Because ligand adsorption does not induce s ignificant changes in surface photovoltage, we conclude that changes i n work function are due to changes in electron affinity rather than in band bending. This means that ligand adsorption does not induce charg e transfer between the surface and the semiconductor but rather adds a surface dipole. Changes in band bending do occur, however, upon conve ntional etching.