Variation of band gap energy and photoluminescence characteristics with Te composition of ZnS1−xTex epilayers grown by hot-wall epitaxy

Abstract ZnS 1− x Te x ternary alloy epilayers were grown on GaAs (1 0 0) substrates by hot-wall epitaxy (HWE), and the dependence of their band gap energy and photoluminescence (PL) characteristics on the Te composition x was investigated. The spectrophotometer measurement results demonstrated that the room temperature band gap energy varied with the Te composition x . The band gap energy showed the strong bowing effect given by E g ( x )=3.73−5.27 x +3.80 x 2 . The PL peaks of ZnS 1− x Te x epilayers shifted to the lower energy with increasing Te composition x . For x >0.69, the PL peak energy was very close to the band gap energy. Bowing parameter, 3.80, was closer to the value of Bernard et al., 3.83, and was a little larger than the previous other results. Strong emission ranging from blue to yellow was observed at room temperature. Also, the relations between Te n ( n =1,2,3) atoms of the ZnS 1− x Te x epilayers and the exciton emission at room temperature were investigated.