Surface Morphology of PLD ZnO Thin Films

The surface morphology of the PLD grown ZnO-based films is important for the interface quality of multilayer structures, including quantum wells with thickness of a few nanometer only, for the formation of metal-semiconductor Schottky contacts and for the optical emission properties. Therefore, the control and optimization of surface properties is essential for the successful application of ZnO thin films in related device configurations. 

The surface morphology of ZnO films on sapphire, 3C-SiC/Si, and 6H-SiC substrates was also investigated by scanning electron microscopy (SEM) as 

The PLD grown ZnO-based films on sapphire can be arranged as follows 

For that, high Hall mobility values well above 100 up to 150 cm2 (V s) 1 were obtained reproducibly for carrier concentrations from about 6 x 1015 up to 3 x 1016cm-3. 

A deeper insight into the lateral electrical homogeneity of the films, the limiting mechanisms of the Hall mobility, and the thermal activation energies of shallow and deep defect levels can be gained by temperature-dependent Hall and deep level transient spectroscopy (DLTS) measurements [57,59,60]. To give an example, the temperature dependence of the Hall mobility and 

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