Enhanced Electrical and Optical Characteristics of Co/Phenol Red (PR)/Silicon Hybrid Heterojunction for Photodiode and Thermal Applications

A Co/phenol red (PR)/n-Si/Al device has been fabricated and its current-voltage (I-V) characteristics measured between 80 K and 460 K. Junction parameters of the device, such as the ideality factor, barrier height, interface state density, and series resistance (R-s), were determined using standard thermionic emission theory, the Cheung function, and the Norde method. The application of these approaches revealed that n varied between 4.66 and 1.70 in the temperature range of 80 K to 460 K, while phi(b) varied between 0.24 eV and 0.83 eV in the same temperature range. These variations of n and phi(b) can be attributed to the barrier height inhomogeneity in the device. Although PR is generally used in biological applications such as cell culture, it has been observed that such Co/phenol red/n-Si/Al devices may be critical candidates for use in thermal sensors and photodiode applications due to their photoresponse and low-temperature operation for reverse-bias I-V measurements. Furthermore, PR is an alternative to semiconductor materials commonly used in such applications.