Room-temperature telecom Si:Te PIN planar photodiodes: A study on optimizing device dimensions

The lack of efficient, cost-effective, room-temperature, and silicon-based photodetectors operating at the telecom bands has posed a persistent challenge in the realm of silicon photonics. One potential solution lies in introducing an impurity band within the silicon bandgap, offering a pathway to create a silicon-based photodetector that not only meets the requirements but also benefits from seamless integration with mature CMOS technology. Here, we report on enhancing device performance by introducing geometric modifications while retaining the doping concentration, device area, and operating conditions. The modified devices showcase improved responsivities, reaching approximately 3 × 10−2 A/W at 1300 nm (O band) and 1 × 10−2 A/W at 1500 nm (C band). These values significantly surpass prior work on Si:Te planar photodetectors, demonstrating an improvement of over 30 times. The noise equivalent power however was found to unavoidably increase by one order of magnitude to 10−6 (W /Hz).