Nanoscale physics

Strong angular dependence of photoluminescence spectra
in CdMgTe/CdMnTe/CdMgTe quantum well heterostructures
A.V. Komarov1, Z.Ya. Zhuchenko2, G.G. Tarasov2,  M.M. Glazov3, E.L. Ivchenko3 
1 Institute of Physics, Natl. Acad. of Sci. of Ukraine. Prospect Nauki, 46, Kiev-03028, Ukraine. 
E-mail: komarov@iop.kiev.ua
2 Institute of Semiconductor Physics, Natl. Acad. of Sci. of Ukraine. Prospect Nauki, 41, Kiev-03028, Ukraine.

3Ioffe Physical-Technical Institute, Politekhnicheskaya 26, St Petersburg 194021, Russian Federation 

The uncoupled quantum wells (QWs) Cd1-yMgyTe/Cd1-xMnxTe/Cd1-yMgyTe of diluted magnetic semiconductors grown by molecular beam epitaxy on the semi-insulating substrate GaAs (100) are of great interest for various applications in   spintronics. In this study the structures of Cd1-xMnxTe QWs (x=0, 0.014, 0.025, 0.05) with different QW widths dQW separated by thick barrier layer Cd1-уMgуTe (y=0.2, dQW =30.8 nm) are under investigation. It is found that photoluminescence spectra of this structure are strongly dependent on the geometry of excitation. 

At normal incidence of exciting light spectrum of photoluminescence (PL) consists of four single bands corresponding to four available quantum wells of different composition and thickness. Under sliding incidence (angle ≈1700) the line shape of PL spectrum drastically changes: only PL from one selected QW remains transforming in two band structure. Such striking difference of PL spectra of multiwell structure at normal and sliding incidence is explained by variation of the QW thickness in the plane of interfaces.