| dc.description |
A method of investigating an interface of the Schottky barrier by a photovoltaic effect, earlier introduced by the same author, is examined here in a complex analysis of the interfacial layer effects in Cu/Cu<sub>2</sub>O junctions. This approach assumes construction of the n–V<sub>oc</sub> (nonideality factor vs open circuit voltage) diagram for the devices studied and its analysis in terms of theoretical model of the tunnel MIS Schottky diode. Two interesting cases from a tutorial viewpoint are considered: the case of native interfacial layer (A) and that of intentionally modified native interfacial layer (B).The first one was studied for the resistively evaporated Cu/Cu<sub>2</sub>O junctions whereas the second one was experimentally achieved by low energy H<sup>+</sup> ion irradiation of the same junction. In each case, different V<sub>oc</sub> vs n behavior has been noticed at the diagram suggesting that different parameters of an interfacial layer are playing a dominant role. In the case A, the experimental n–V<sub>oc</sub> diagram, where V<sub>oc</sub> was almost proportional to n, has been correctly described by theory when assuming constant thickness of an interfacial layer (iso-thickness line). Thus, an increase of n and V<sub>oc</sub> has been associated with rising density of interface states. In the case B, a significant growth of V<sub>oc</sub> due to H<sup>+</sup> ion irradiation, accompanied by relatively weak increase of n, has been approximated by iso-density (of interface states) lines at the n–V<sub>oc</sub> diagram. Therefore the whole effect was ascribed to the rise of an interfacial layer thickness. The possible origin of the native interfacial layer in Cu/Cu<sub>2</sub>O junctions as well as the mechanism of its modification by H<sup>+</sup> ion beam have been also explained here. |
