Ultra-Narrowband Optical Absorption by MoS2 and WS2 TMDC Monolayers Using Octonacci and Pell Defective Quasi-Photonic Crystals

Transition metal dichalcogenides (TMDCs) have attained immense importance in the field of optoelectronics and photonics due to their idiosyncratic characteristics. An ultra-narrowband photonic absorber in the visible wavelength range is suggested here for MoS₂ and WS₂ TMDC materials using Octonacci and Pell defective quasi-photonic crystals (DQPCs). A tunable defect mode is created for high optical absorption using DQPCs. By varying some parameters such as periodicity, type of sequence, and generation number in DQPCs, the wavelength and magnitude of absorption can be adjusted. Absorption spectra for different DQPC structures are calculated using the Transfer Matrix Method (TMM). For both Octonacci and Pell DQPCs, absorption as high as 90% or above can be achieved. The values of maximum absorption and peak wavelength can be tuned by changing the values of periodicity and generation number respectively. For Octonacci and Pell DQPCs, SiO₂ and Si₃N₄ are used as alternating materials.