Investigating the Characteristics of Metal Oxide Based Photodiode

摘要

UV rays are causing severe threat to environment and human beings. The health issues caused by the UV rays include deadly cancer disease, cataract etc. it can impact the lives of plants and other living organisms. The impact of UV rays on climate change over various parts of earth is higher. In this scenario the need for efficient UV detection mechanism is highly requested. ZnO is a widely used metal oxide for UV ray detection due to its low band gap energy of 3. 2eV and high photoconductivity in UV region. We adopt a heterojunction schottky diode with ZnO for UV ray detection. A schottky n-ZnO-Si structure is simulated it is found to have a responsivity of 132mA/W. In order to improve the sensitivity of the structure a p type guard ring structure implanted over an is placed in between schottky contact and ZnO, it is implanted over an n well structure. This structure is reported to have responsivity of 323mA/W and rise and fall time of 2ns and Sns respectively at -2V reverse bias for Schottky platinum contact. Additional A$l_{2}O_{3}$ buffer is added in betweenn - ZnO and n-Si substrate in order to avoid the charge transfer and improve performance of ZnO detectors. The simulations are done on Silvaco atlas version 4. 2.6.R