Effect of the MIS structure with MgF2 on CELIV measurements

Abstract

The effect of the metal-insulator-semiconductor (MIS) structure with magnesium fluoride (MgF2) was investigated for the charge extraction by the linearly increasing voltage method using metal-insulator-semiconductor structure (MIS-CELIV). Hole mobilities of N,N´-bis(naphthalen-1-yl)-N,N´-bis(phenyl)-benzidine (NPB) films were measured for devices with a MgF2 insulator above or below the NPB film. Both devices yielded ideal MIS-CELIV signals and hole mobilities, which are consistent with those for conventional Si/SiO2 devices. The validity of the estimated mobilities were discussed by analyzing the amount of extracted charges affected by the surface traps on MgF2. The usage of an evaporable insulating material can allow the free placement of the insulating layer; enabling configurations where the underlying layer does not falsely influence the organic layer.