A growth of A-Z phthalocyanine layers onto Si by thermal evaporation process to achieve organic heterojunction diodes

Abstract Thermally evaporated organic heterojunction (OHJ) diodes based on A-Z phthalocyanine (ZnPc/pSi and AlPc/Si) are investigated. Here, we study the electronic parameters of ZnPc/pSi and AlPc/Si organic heterojunction diodes. Such organic heterojunctions are produced by thermal evaporation process in vacuum at very low pressure. For this purpose, the current-voltage (I-V) characteristics at room temperature under dark conditions for the organic aluminum and zinc (A-Z) phthalocyanine materials are measured. Firstly, the electronic parameters of the organic heterojunctions including ideality factor n, barrier height (Φb), series resistance (RS) are extracted via Cheung and Norde methods respectively. A high rectification ratio (RR) in order of 2 × 104 is recorded for ZnPc/p-Si contacts. Non-ideal behavior of AZPc OHJ is revealed n∼2.4, series resistance and barrier height are of 2kΩ and 0.4 eV. Secondly, the conduction mechanism of both AlPc/Si and ZnPc/Si contacts are investigated. SCLC is the dominated conduction mechanism throughout the OHJ device.