Surface quantum wells of gallium nitride have been grown by Metal Organic Vapor Phase Epitaxy on top of AlGaN/GaN heterostructures. One boundary of the quantum well is vacuum (or air)/GaN interface, the other is GaN/AlGaN interface, and the width of the quantum well is the thickness of gallium nitride cap, and quantum confinement is demonstrate by the energy shift in photoluminescence, and cathodoluminescence as the GaN cap thickness is varied. The efficiency of the quantum well emission is sensitive to the surface environment and resulting surface recombination velocity. In this study the surface is altered by surface preparation treatments and resulting in changes in the luminescence. The changes in the efficiency of quantum well luminescence with surface treatments are attributed to changes in surface recombination velocity and surface electric fields.