TY - JOUR
T1 - Optical properties of Zn 1-xMn xTe epilayers grown by molecular beam epitaxy
AU - Shih, Yu-Tai
AU - Chiang, W. C.
AU - Yang, C. S.
AU - Kuo, M. C.
AU - Chou, W. C.
PY - 2002/9/1
Y1 - 2002/9/1
N2 - Zn 1-xMn xTe (0≤x≤0.268) epilayers were grown on GaAs(001) substrates by molecular beam epitaxy. The optical properties of the epilayers were studied using reflectivity, transmission, and photoluminescence (PL) measurements. The energy gaps of the epilayers were found to increase linearly with Mn concentration. From the PL spectra, a redshift of the PL peaks was observed as the temperature was increased. The exciton activation energies of the epilayers were determined by the plots of logarithmic-integrated PL intensity versus inverse temperature. Accordingly, they increase with Mn concentration. The Varshni and O'Donnell relations, which mimic the temperature dependence of semiconductor energy gaps were used to fit the experimental data [Y. P. Varshni, Physica 34, 149 (1967); R. P. O'Donnell and X. Chen, Appl. Phys. Lett. 58, 2924 (1991)]. Good fits were obtained by both relations. From the fitted results, the entropy of formation of electron-hole pairs in the Zn 1-xMn xTe epilayers at room temperature was estimated to be roughly 0.5 meV/K.
AB - Zn 1-xMn xTe (0≤x≤0.268) epilayers were grown on GaAs(001) substrates by molecular beam epitaxy. The optical properties of the epilayers were studied using reflectivity, transmission, and photoluminescence (PL) measurements. The energy gaps of the epilayers were found to increase linearly with Mn concentration. From the PL spectra, a redshift of the PL peaks was observed as the temperature was increased. The exciton activation energies of the epilayers were determined by the plots of logarithmic-integrated PL intensity versus inverse temperature. Accordingly, they increase with Mn concentration. The Varshni and O'Donnell relations, which mimic the temperature dependence of semiconductor energy gaps were used to fit the experimental data [Y. P. Varshni, Physica 34, 149 (1967); R. P. O'Donnell and X. Chen, Appl. Phys. Lett. 58, 2924 (1991)]. Good fits were obtained by both relations. From the fitted results, the entropy of formation of electron-hole pairs in the Zn 1-xMn xTe epilayers at room temperature was estimated to be roughly 0.5 meV/K.
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U2 - 10.1063/1.1495065
DO - 10.1063/1.1495065
M3 - Article
AN - SCOPUS:0036733876
VL - 92
SP - 2446
EP - 2450
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 5
ER -