Abstract
The photoelectronic properties of -type ZnSe: Cu and of -type self-activated ZnSe(SA) have been investigated in single crystals. Results for ZnSe: Cu may be described by a multivalent-copper-impurity model in which and ions substituting on the Zn sublattice are responsible for the red and green luminescence bands, respectively. The green luminescence emission (2.34 eV) is from the conduction band to the empty center. One of the red emission bands (1.97 eV) is from the conduction band to the empty ′ center; a second red band (1.95 eV) is from a shallow level near the conduction band to the empty ′ center. The ′ center is also the major sensitizing center for -type photoconductivity in -type ZnSe: Cu, and it is the dominant acceptor center controlling -type conductivity. Optical absorption in the infrared is due to an internal transition within the , which has an (Ar) electronic configuration, plus a transition from the valence band to the empty ′ center. Several annealing and impurity-incorporation experiments performed on ZnSe: Cu support this model for the Cu luminescence centers. The sensitizing center for -type photoconductivity in -type ZnSe(SA) is not the same as that associated with ′ in -type ZnSe: Cu; it lies closer to the valence band and has a capture cross section for electrons that of the ′ sensitizing center.
- Received 9 February 1968
DOI:https://doi.org/10.1103/PhysRev.171.903
©1968 American Physical Society