Effect of Rare Earth Doping on the Optical Quality of А²В⁶ Semiconductors

It is well known that rare earth elements (RE) have a characteristic configuration of their electron shell, namely, 4d¹⁰4fⁿ5s²5p⁶6s² (n=1-14), where 4f-electrons form an unfilled electronic shell shielded by several filled shells [1,2]. Thus, doping of semiconductor materials with RE leads to the appearance of a system of discrete energy levels associated with the ground and excited states of RE ions. These states are strongly localized and weakly perceive the vibrations of the crystalline lattice. Therefore, the emission of RE ions, caused by optical transitions from excited to ground states of the ions, includes narrow lines that are commonly used for developing laser systems [3]. In addition, the development of LEDs for a wide spectral region requires using А3В5 semiconductors with wide band gaps doped with triply-charged RE ions. In this case, isovalent substitution of cations occurs.