| 초록 |
Temperature-dependent photocurrent (PC) behavior of unintentional p-type BaIn2Se4 layers grown through the hot wall epitaxy method was investigated. From the PC measurement, three peaks A, B, and C were associated with the intrinsic transitions from the valence band states of Γ3(A), Γ4(B), and Γ5(C) to the conduction band state of Γ1, respectively. Thus, an interval on the valence band splitting of the crystal field and the spin orbit splitting was observed to be 0.0903 and 0.1507 eV, respectively. Furthermore, the temperature dependence of the optical bandgap energy could be well expressed by using Varshni's formula However, the PC intensities decreased with decreasing temperature. In the log Jph vs 1/T plot, the dominant level at the high-temperature region was observed and its value was 29.1 meV. This level corresponds to the activation energy for the electronic transition from the edge of the valence band to the shallow acceptor levels caused by these native defects. Consequently, we suggest that with decreasing temperature, the trapping centers due to native defects in BaIn2Se4 layers are responsible for this PC-intensity decrease. |
