Room‐Temperature Yellow Emission of a High Cd Content (x = 0.70), Highly Strained, Layer‐by‐Layer Grown Zn1−xCdxSe/ZnSe Quantum Well

The results of the growth and characterization of an 8 monolayers (MLs) thick Zn1−xCdxSe/ZnSe quantum well (QW) with quite high Cd content (x = 0.70) are presented. At room temperature (RT), the QW presents yellow excitonic emission at 2.179 eV (569 nm, same color as the yellow line of a Kr ion laser). Despite the large Cd content, the RT photoluminescence spectrum shows a well‐defined, symmetric excitonic peak with relatively narrow full width at half maximum, indicating a good structural quality of the QW that is attributed to the sequential layer‐by‐layer growth mode achieved by the use of the submonolayer pulsed beam epitaxy (SPBE) technique. The ZnSe barriers are grown by molecular beam epitaxy (MBE); the QW heterostructure is deposited on top of a GaAs(001) substrate at 275 °C. Scanning transmission electron microscopy indicates a homogeneous smooth QW layer. The evolution of the excitonic emission energy with increasing temperature in the 19–300 K range shows the well‐known S‐shaped behavior that is interpreted in terms of exciton migration. A homogeneous, 8 monolayers (≈2.5 nm) thick, Zn1−xCdxSe/ZnSe quantum well with a difficult to obtain high Cd content is grown in a sequential layer‐by‐layer mode by submonolayer pulsed beam epitaxy (SPBE). Yellow emission at room temperature is visible to the naked eye; its peak at 2.179 eV (569 nm) is in precise coincidence with the Kr ion laser yellow line.