The authors report a comparative study on ex situ passivation of a near-surface GaAs0.86P0.14/Al0.6Ga0.4As quantum well using various sulfide solutions and nitrogen plasma treatments. The built-in surface electric field is changed via band bending by applying various surface passivation conditions. The band bending is measured using x-ray photoelectron spectroscopy. Reduction in surface electric field in the range of 10-35 kV/cm is observed depending on different passivation conditions. The photoreflectance spectra show enhancement in intensity and blueshift of similar to 3 meV accompanied by significant reduction in the broadening parameter of the observed e(1)-lh(1) transitions. Among all the methods studied here, passivation by Na2S center dot xH(2)O is found to be most effective as it removes the native oxide layer completely leading to almost flat band condition. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3490021]