Electrical and frequency dependence characteristics of Ti/polyethylene oxide (PEO)/p-type InP organic-inorganic Schottky junction

A thin polyethylene oxide (PEO) is formed on p-type InP substrate as an interlayer for electronic alteration of the Ti/p-InP metal/semiconductor (MS) junction. The electrical and frequency dependence characteristics of the Ti/PEO/p-InP metal/interlayer/semiconductor (MIS) junction are explored by I-V, C-V-f and G-f measurements. The mean ideality factor and barrier height (BH) are assessed to be 1.93 and 0.74 eV (I-V), and 2.05 and 0.84 eV (I-V) for the MS and MIS junctions, respectively. It is found to the BH is increased by 100 meV for the MIS junction contrasted to the MS junction, indicating the BH is modified by the polymer interlayer. An average tunnelling BH is also estimated to be chi = 0.11 eV for the MIS junction. Moreover, the interface state density (N-ss) is estimated for both MS and MIS junctions by forward I-V characteristics. The Nss and relaxation time (tau) are also determined from the C-f and G-f data. The Nss assessed by I-V and C-V methods are comparable with the values extracted by C-f and G-f data. The dielectric constant (epsilon'), dielectric loss (epsilon ''), tangent loss (tan delta) and ac electrical conductivity (sac) parameters are extracted and discussed in the frequency range of 1 kHz-1 MHz at various bias voltage for the MIS junction. The epsilon' and epsilon '' values are found to be reduced with increasing frequency. (C) 2016 Elsevier B.V. All rights reserved.