Optoelectronic Properties of Triphenylamine Organic Thin Film Layered Al/p-Si /TPA/Al Heterojunction for Photodiode Application

Abstract

Organic semiconductors provide many advantages in diode fabrication due to their variable electrical properties, flexibility and easy and cheap production processes. In this study, triphenylamine (TPA) organic compound was used for the Al/p-Si/TPA/Al Schottky structure. The effect of the triphenylamine on the electrical properties of the produced diode was studied by current-voltage measurements in dark and under various illumination intensities. The main electrical parameters such as barrier height (ΦB), ideality factor (n), series resistance (R s), and interface state density (N ss) were obtained from the I-V characteristics. The n, and R s values of the diode were found as 1.88, 0.80 eV and 2195 Ω for dark, and 3.96, 0.71 eV and 17 Ω for 100 mW cm−2 illumination intensity. Besides, the fabricated device exhibited photodiode behavior as obtained from the photocurrent measurement for the diode, depending on the illumination intensity. Additionally, it was found that the Al/p-Si/TPA/Al diode had a higher photocurrent (I ph ) in illuminated conditions than in dark conditions. The main photovoltaic parameters such as open circuit voltage (V oc ) and short circuit current (I sc ) were also investigated. Photo-responsivity and response time (τ r, τ d) of the diode was obtained as 0,015 A W−1 and 800 ms respectively. All these results show that the Al/p-Si/TPA/Al diode has potential in optoelectronic device applications.