Proton irradiation effects on semiconductor cadmium selenide/zinc sulfide core/shell nanocrystals

The absorbance and photoluminescence measurement of semiconductor CdSe/ZnS core shell nanocrystals were reviewed and investigated after they were exposed to proton irradiation. The CdSe/ZnS core shell nanocrystals of 3.2nm and 4.4nm were commercially purchased and investigated. These nanocrystals were embedded in UV resin. Proton irradiation of energy 2MeV was applied at doses from 3 x 1013 protons cm-2 to 1.47 x 10 15 protons cm-2 for both nanocrystal sizes. Absorbance measurements were conducted at 300K. Results from absorbance measurements showed slight broadening of the first exciton peak of both samples but was most noticeable in the 3.2nm nanocrystal sample. UV resin proton irradiation was potentially attributed to this result. Photoluminescence results were conducted at both 300k and 77K. An increase in intensity was observed at the first proton irradiation dose but then intensity degradation as the irradiation dose increased. This first increase in PL intensity was potentially due the reduction of the phonon bottleneck or displacement damage causing additional relaxation paths. Though degradation was observed in the absorbance, photoluminescence and integrated area of these spectrums, the tolerance displayed throughout the doses without totally diminishing the optical spectrums, makes CdSe/ZnS a competitive candidate for future optoelectronic material for space applications.