Polarized Raman spectra of selenium species confined in nanochannels of AlPO4-5 single crystals

Selenium has been incorporated into the channels of AlPO4-5 (AFI) single crystals by vapor adsorption as well as by molten Se injection. Results have been found to be similar for both methods. From Raman spectra, we have concluded that single helical Se chains and Se8 molecules are formed inside the AFI channels. Moreover, we have found trigonal Se in meso-channels of AFI–Se crystals. Single chains and chains in trigonal Se are oriented along the c-axis of the AFI crystal. Se8 molecules are mainly oriented by 4-fold axis along the c-axis of the AFI crystal.