Photoluminescence and surface photovoltage properties of ZnSe nanoribbons

ZnSe nanoribbons were synthesized with chemical vapor deposition route. The excitation power-dependent photoluminescence and surface photovoltage (SPV) techniques were used to study the optoelectronic properties of the as-grown ZnSe nanoribbons. Three deep defect (DD)-related emission bands, respectively, centered at 623 nm (DD1), 563 nm (DD2) and 525 nm (DD3), emerge orderly with increasing the excitation power, which is attributed to the saturation of the DD states from deeper to shallower level. The SPV spectrum and the corresponding phase spectrum show that DD1 mainly acts as recombination center, while DD2 and DD3 can act as both the recombination center and electron traps. The influence of the trapping electrons on the SPV response dynamic was studied with transient SPV.