Fig. 1. (Color online) SEM, HRTEM, STEM and EDS measurements performed in H1 sample. (a) SEM image from the surface of the CdMnTe film grown on Si(111) substrate. (b) HRTEM image of the interface between CdMnTe and Si(111) substrate. (c) and (d) STEM images showing the interface of H1 sample indicating the CdTe layer (yellow arrows) in the formation of the CdMnTe/CdTe/CdMnTe heterostructure. (e)–(g) EDS maps from (d) for Te, Cd and Mn elements.

Fig. 2. (Color online) (a) and (b) The illustrations represent the CdMnTe/CdTe/CdMnTe heterostructures (described in experimental section) grown on Si(111) with a high roughness interface formed from the result of a growth based on 3D islands nucleated on Si surface. We have an inhomogeneously sized and randomly formed three-dimensional CdTe structures in (b). (c)−(e) Low temperature normalized macro photoluminescence spectra for samples for H1, H2, and H3 taken at power densities of 28, 710, and 852 W/cm², respectively. The power density used in (d) was 1.4 W/cm² for H1 sample and 2.8 W/cm² for (e) H3 sample.

Fig. 3. (Color online) (a) Low temperature integrated PL intensity of the main emission (QW-like emission around 1.61 eV at 8 K) and the lower energy emission (defects and bound exciton states around 1.48 eV at 8 K) for sample H1 represented in black circles and triangles, respectively. Solid lines are fit to the data. (b) Integrated PL of the main emission (1.79 eV) in sample H3. (c) Representative spectra of temperature-dependent macro PL for H1 (QW-like emission around 1.61 eV at 10 K). (d) Peak energy (black circles, left vertical scale) and FWHM (purple circles, right vertical scale) as a function of temperature for the main emission of sample H1 around 1.61 eV at 10 K (QW-like emission). (e) Same as (d) for the lower energy emission around 1.48 eV at 10 K (defects and bound exciton states) detected in sample H1. Red solid lines in (d) and (e) represent the calculation using the Varshni equation. (f) Temperature-dependent integrated PL peak of the main (circles) and lower energy (triangles) emissions for H1.

Fig. 4. (Color online) (a) Low temperature μ-PL results measured at different laser excitation powers for (a) H1 and (b) H3 heterostructures. The two spectra at the top marked with asterisks (*) were measured at different positions. (c) FWHM for arbitrarily chosen emissions measured with the same power of 1 μW for H1 (black filled square) and H3 (blue filled square). (d) Intensity map of low temperature μ-PL for H3.

Fig. 5. (Color online) Polarization-resolved low temperature μ-PL results for H1 heterostructure. (a) Spectra obtained in two different positions on the sample for detection of polarization σ+ (black solid line) and σ− (red solid line). (b) μ-PL intensity map and (c) corresponding degree of spin polarization.