Study of Photoluminescence Mechanism of Rare Earth Ions in Compound-Semiconductors by Means of Magneto-Circular Photoluminescence

利用光弹调制器建立了红宝石（Al_2O_3：Cr^<3+>）的磁圆吸收二色性（MCDA）和磁圆光致发光（MCPL）光谱测量系统，测量了25 K下红宝石的MCPL和MCDA光谱。这些光谱进行了分析的配位场理论。在电弧成像炉中用浮区法制备了CaS：Eu^<2+>单晶，测量了MCPL和MCDA的光谱。在MCPL和MCDA中观察到的精细结构被归属为三条f-d跃迁的零声子线（ZPL）和与ZPL相关的声子边线。在这些晶体中测量的PL光谱显示了主体晶体的宽黄色带和叠加在该带上的几条Tb^<3+>-线。MCDA谱发现了Tb原子的激发态，而PLE谱和光吸收谱没有发现Tb^<3+>激发态的谱线，因此MCPL和MCDA技术成为表征化合物半导体中稀土离子和过渡离子电子结构的有力工具。

A system of spectroscopic measurement for manetocircular dichroism of absorption(MCDA)and for magnatocircular photoluminescence(MCPL)was constructed using a photoelastic modulator.Using this technique, MCPL, as well as MCDA spectra in ruby (Al_2O_3 : Cr^<3+>) at 25 K were measured. These spectra were analyzed in terms of the ligand-field theory. However, the analysis failed to explain the observed MCPL lineshape of R_1-line.Spectra of MCPL and MCDA were also measured in a CaS : Eu^<2+> single crystal prepared by floating-zone technique in an arc-image furnace. Fine structures observed in MCPL and MCDA were assigned to three zero-phonon lines(ZPL)of f-d transition and phonon-side lines associated with the ZPL.Tb-doped single crystals of CuAlS_2 were grown by the chemical transport technique. PL spectra measured in these crystals showed a broad yellow band of host crystal and several Tb^<3+>-lines superposed on the band. Excited state of the Tb-origin energy level was found by the MCDA spectrum, although PLE(photoluminescence excitation)and optical absorption spectra showed no lines associated with the excited state of Tb^<3+>.Thus MCPL and MCDA techniques turns out to be a powerful tool for the characterization of electronic structures of rare-earth and transition ions in compound-semiconductors.