1 research outputs found
Wet Chemical Functionalization of GaP(111)B through a Williamson Ether-Type Reaction
Functionalization of crystalline
gallium phosphide (GaP) (111)ÂB
interfaces has been performed through the formation of P–O–<i>R</i> surface bonds. The approach described herein parallels
classical Williamson ether synthesis, where hydroxyl groups on etched
GaP(111)B surfaces were reacted with halogenated reactants. Grazing
angle total internal reflectance infrared spectra showed increased
intensities for −CH<sub>2</sub>– and −CH<sub>3</sub> asymmetric and symmetric stretches after reaction with long
alkyl halides. Changes in the X-ray photoelectron spectra collected
before and after reaction separately corroborated surface attachment
to GaP(111)ÂB. Static sessile drop water contact angle measurements
for GaP(111)B separately showed increased hydrophobicity following
surface modification with long alkyl chains. The surface functionalization
reaction rate was increased by the addition of non-nucleophilic bases,
consistent with surface deprotonation as the rate-limiting step. Separately,
photoelectrochemical measurements conducted before and after reaction
with alkyl halides at long wavelengths (λ > 545 nm) showed
surface
attachment decreased sub-band-gap photocurrents, implying lowered
activity of surface traps. Conversely, photoelectrochemical measurements
performed after functionalization of p-GaP(111)B with Coomassie Blue
sulfonyl chloride showed evidence of persistent sensitized hole injection
from the dye into p-GaP