Morphology, twinning, and photoluminescence of ZnTe crystals grown by chemical synthesis from vapor-phase components

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

“…Table 7 summarizes these data. Optical transitions with energy (2.381÷2.383) eV were observed in [68,[75][76][77][78][79][80][81][82][84][85][86] where authors had studied monocrystalline or bulk polycrystalline ZnTe of high structural and optical quality. These transitions are commonly relating to a free exciton (X).…”

“…These impurities form in the gap of the material more narrower levels than the acceptor ones. The line with Ei=2.371 eV which is energetically closed to that considered above is due to radiation of bound excitons [76][77][78]81]; nevertheless the impurity (acceptor) in this complex has (obviously) somewhat larger energy level causing other energy of the stripe. These acceptors are native defects and uncontrollable excessive impurities (Li, Na, Ag, Cu).…”

“…Earlier [82] the PL line of Ei = (2.374÷2.375) eV was suggested to be caused by the exciton bound on neutral acceptor (zinc vacancy VZn). Further [76][77][78] it was shown that other acceptor centers take part in forming such an excitonic complex, in particular, acceptor centers due to uncontrollable impurities (Li, Cu) in ZnTe are of interest. However, in the most recent works [68,81] this line is ascribed to the exciton localized on shallow neutral donor (atoms of uncontrollable impurities from 3 rd and 7 th Groups of the Periodical System (In, Ga, Al, Cl, Br.…”

“…The set of nearest lines in the energy range Е = (2.30÷2.33) eV and Е = (2.17÷2.25) eV authors [76][77][78][79] ascribe to the electron transitions from the conductance band to the shallow acceptor levels formed by Li or Cu atoms and their phonon repetitions (LO -25.5 meV). There are stripes 2SLi, 3SbLi, (e-A) Li, 2P Li, 4SbLi, 4SbLi-LO, 2SCu, 3SbCu, 4SbCu, 2Sb Cu -LO, 2Sb Cu -2LO and others.…”

“…Table 7. Analysis and interpretation of the PL peaks are carried out according to reference data [75][76][77][78][79][80][81][82][83][84][85][86][87][88][89]. We calculated activation energies of corresponding processes using the expression (26).…”