Journal Article 2D tellurium 2D van der Waals heterostructures Review defect engineering electronics ferroelectric polarization floating gate in-sensor reservoir computing multimodal reservoir computing neuromorphic computing optical communication band optoelectronic memory device optoelectronic memory devices optoelectronics reconfigurable memory device synthesis methods tellurium tellurium nanoflake van der Waals heterostructure van der Waals heterostructures van der Waals materials