Articles you may be interested inStructure and optical properties of a-plane ZnO/Zn0.9Mg0.1O multiple quantum wells grown on r-plane sapphire substrates by pulsed laser deposition Erratum: "Aging effect and origin of deep-level emission in ZnO thin film deposited by pulsed laser deposition" [Appl. Phys. Lett.86, 221910 (2005)] Appl. Phys. Lett. 87, 039902 (2005); 10.1063/1.1978974 Aging effect and origin of deep-level emission in ZnO thin film deposited by pulsed laser deposition Appl. Phys. Lett. 86, 221910 (2005); 10.1063/1.1939078Er-doped ZnO thin films grown by pulsed-laser deposition

Zn 1−x Cd x O͑1120͒ films have been grown on ͑0112͒ sapphire ͑r-plane͒ substrates by metal-organic vapor phase epitaxy. A 800-nm-thick ZnO buffer, deposited prior to the alloy growth, helps to prevent the formation of pure CdO. A maximum uniform Cd incorporation of 8.5 at. % has been determined by Rutherford backscattering spectrometry. Higher Cd contents lead to the coexistence of Zn 1−x Cd x O alloys of different compositions within the same film. The near band-edge photoluminescence emission shifts gradually to lower energies as Cd is incorporated and reaches 2.93 eV for the highest Cd concentration ͑8.5 at. %͒. The lattice deformation, due to Cd incorporation, has been described using a new reference frame in which the lattice distortions are directly related to the a-plane surface structure. Cd introduction does not affect the c lattice parameter but expands the lattice along the two perpendicular directions, ͓1120͔ and ͓1100͔, resulting in a quadratic volume increase.

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Mg x Zn 1−x O/ZnO/Mg x Zn 1−x O quantum wells (QWs) (0.12 ≤ x ≤ 0.15) have been grown on aplane sapphire substrates by pulsed laser deposition. The nominal ZnO well layer thickness lies between 1.2 nm and 6 nm. Atomic force microscopy (AFM) investigations at ZnO/Mg x Zn 1−x O heterostructures show the film-like structure of the ZnO layers. Their root mean square surface roughness of ~ 0.5 nm gives information about the interface roughness in the QWs. AFM results from the Mg x Zn 1−x O barrier layers show the same surface structure and roughness. We confirmed the lateral homogeneity of the Mg distribution in the Mg x Zn 1−x O barrier layers by scanning cathodoluminescence measurements. The QWs show a bright and laterally homogeneous luminescence, suggesting good crystalline quality of the ZnO wells. The measured QW photoluminescence energies agree well with calculated values and display the presence of the quantum-confined Stark effect. As a result of quantum confinement a high-energy shift of the ZnO excitonic photoluminescence of 222 meV is observed in the thinnest QW. Mater. Res. Soc. Symp. Proc. Vol. 957