The present invention relates to an electrical and/or opto-electrical characterisation method for testing large-area semiconductor devices in production, the method comprising the steps of providing a first electrode and placing it into electrical contact with a contact area of a conducting layer of a semiconductor device; providing a movable electrode assembly, comprising a container holding an electrolyte solution and at least a second electrode; immersing the second electrode into the electrolyte solution; positioning the electrode assembly such that the electrolyte solution places the second electrode into electrical contact with a top surface of the semiconductor device; and scanning the movable electrode assembly relative to the top surface of the semiconductor device while performing electrical measurements. It also relates to a corresponding electrical and/or opto-electrical characterisation device comprising a first electrode, a movable electrode assembly with a container holding an electrolyte solution and a second electrode immersed into it and scanning means.