Structural and photoluminescence properties of Cr2+:ZnSe films deposited by radiofrequency magnetron co-sputtering for mid-infrared microlaser applications

Highly crystallised Cr2+:ZnSe cubic films with a strong <1 1 1> orientation were deposited at room temperature by radiofrequency magnetron co-sputtering. The effect of the sputtering power and the chromium quantity on the structural and optical properties of the deposited films has been investigated by means of X-ray diffraction and reflectivity, transmission electron microscopy and photoluminescence studies. The room temperature photoluminescence spectra under direct excitation (1850 nm) revealed that chromium has been incorporated in the Cr2+ active state and the optimal deposition parameters have been determined. These results pave the route to the fabrication of future optically or electrically pumped microlaser broadly tunable in the mid-infrared.