| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Wednesday Sessions |
| Session TF-WeP |
| Session: | Thin Films Poster Session II |
| Presenter: | Chaobin Bi, Jilin University, China |
| Authors: | C. Bi, Jilin University, China C. Hu, Jilin University, China |
| Correspondent: | Click to Email |
Phase change materials (PCMs) are widely used in non-volatile photonic applications due to the large optical contrast (ΔR) caused by phase transitions. However, only ΔR between amorphous and metastable phase are used to achieve the modulation of two optical state, which limits the performance of the photonic device, such as the storage density of the optical disk, the multi-absorption band of the perfect absorber, and the channels of optical switch. Channels. And the ΔR between metastable phase and the stable phase is too small to be considered as a third-order optical state. Therefore, it is necessary to develop new PCMs with three optical state of large ΔR. Here, combined with experiments, theoretical calculations and Tauc-Lorentz model, we reveal the microscopic mechanism and propose a method to increase the ΔR among the three phases. The results show that ΔR is proportional to the change of material disorder and band gap before and after phase transition. On this basis, by introducing an appropriate amount of N (5.8%) into Ge2Sb2Te5, the ΔR between metastable and stable phase is significantly increased from 7% to 22%, exceeding the commercial requirement; meanwhile, the ΔR between amorphous and metastable phase is also increased from 20% to 37%, meaning that the tertiary optical state of large ΔR is obtained. This study not only reveals the origin of ΔR, but also provides new PCMs for research on improving the performance of photonic devices.