A p-type (Cu_1-xAg_x)₂O oxide solution film with cuprite structure for enhanced hole concentration

(Cu_1-xAg_x)₂O oxide films with cuprite structure are presented. The p-type film demonstrates an exceptional increase in hole cconcentration up to 1.18×10²¹cm^-3 with increasing Ag to 33at.%. It is revealed from high-resolution transmission electron microscopy along with X-ray diffraction analysis that the oxide remains a single phase with the Ag content up to 33at.%. Raman spectroscopy measurements exhibit different symmetrical features for the oxide than those of Cu₂O. This suggests that the valence-band edge level can be raised as a result of the incorporation of Ag¹⁺ into Cu₂O, which is verified by the small acceptor ionization energy observed for the (Cu _0.67Ag_0.33)₂O. In addition, the coexistence of Cu¹⁺ and Ag¹⁺ is shown to suppress variable-range-hopping conduction, demonstrating weakly degenerate semiconductor behavior.