The growth of AgGaTe₂ layers on glass substrates with Ag₂Te buffer layer by closed space sublimation method

The AgGaTe₂ layer growth was performed by the closed space sublimation method on the Mo/glass substrate. The Ag₂Te buffer layer was inserted between AgGaTe₂ and Mo layers, to improve the quality of grown layers. Crystallographic properties were analyzed by x-ray diffraction (XRD), and the surface morphologies were analyzed by scanning electron microscopy (SEM). The Ag₂Te layer grown on the Mo/glass exhibited a membrane filter structure from the SEM observation. XRD spectra of layers grown with and without the buffer layer were compared. The AgGaTe₂ layer with the Ag₂Te buffer layer exhibited peaks originating from AgGaTe₂, and a very strong diffraction peak of 112 was observed. On the other hand, it was cleared that the layer grown without the buffer layer exhibited no strong peaks associated with AgGaTe₂, but Ga-Te compounds. From this, crystallographic properties of the AgGaTe₂ layer were drastically improved by the insertion of the Ag₂Te buffer layer. Moreover, the surface morphology exhibited a smooth surface when the Ag₂Te buffer layer was inserted. The nucleation site density of AgGaTe₂ was probably increased since the membrane filter structure exhibited numbers of kinks at the edge. Chemical reaction between Ga and Mo was also eliminated. It was cleared that the insertion of the buffer layer and its surface morphology were an important parameter to grow high quality AgGaTe₂ layers.