Two series of “dislocation” photoluminescence bands in cadmium telluride crystals

Injection and Optical Spectroscopy of Localized States in II-VI Semiconductor Films

“…The similar peak was observed in spectra from the epitaxial films CdTe/BaF2. The line with the same energy was revealed by authors [93] in PL spectra from deformed CdTe single crystals and is supposed to be caused by defects generated in the material due to slip of principal Cd(g)-dislocations. Authors [13,92] explain the peak Ei= 1.538 eV as one of unknown nature.…”

“…As we see the most authors have an unique opinion: the set of lines in the range Е=(1.413÷1.476) eV is due to longitudinal defects (rather dislocations), and their intensity [93] can be a measurement unit of these defects in the material.…”

“…Authors [99] make it more precicely: this peak is caused by the recombination of exciton localized on slipped Cd-dislocations. Authors [93] have investigated The photoluminescence of deformed CdTe single crystals and showed that the peak Еi=1.476 eV is not caused by the Cd-dislocations but is due to the electron states of 60 0 Т (g)-dislocations (-dislocations). So that, the number of authors have the same opinion that this line in PL spectra is caused by the longitudinal defects.…”

“…A modest energetical displacement of lines in spectra from epitaxial films comparing to those from the polycrystalline layers films deposited on glass may be caused by presence of sufficient macrodeformations in the layers CdTe/BaF2. PL spectra from CdTe layers have lines originated from optical transfers with participation of free and bound excitons, transfers valence band -acceptor ( -А), donor-acceptor transfers (DAP), the radiation caused by presence of dislocations or DP (donor pairs, DP) (Y -stripes); the spectra also have a set of lines corresponding to optical transitions where phonons take place (LO -phonon replica) [87][88][89][90][91][92][93][94][95][96][97][98][99]. Activation energies relative to the valence band (while the most samples were of p-type conductivity) were calculated using expression (26) (in analogy with description above).…”