Junction by Diffusion of Elemental Sodium Alone into Bridgman Cu(In, Ga) Se2

The diffusion of elemental sodium into p-type Bridgman-grown CuInSe 2+x has already been shown to create a pn-junction by its presence alone [1], provided the molecular amount of added [Na] exceeds the quantity $2\mathrm{x}+\delta$ [2], (from the excess Se). Here, $\delta$ is the excess of Se found experimentally in the p-type but stoichiometrically-grown material (i.e.with $\mathrm{x}=0$ ). The present contribution demonstrates similar action in Bridgman-grown p-type quaternary Cu(In 1-y ,Ga y )Se 2 , with $\mathrm{y}=0.2$ and 0.3. The existence of deep (more than 6 microns) junctions after the Na-diffusion, is demonstrated by sample lapping and hot probing with, photovoltaic and EBIC action. Information from XPS and XRD is also presented.