Modification of adhesion forces in multiple layers of transition metal dichalcogenides using illumination for micro-actuators

Surface adhesion forces in few layers of layered transition metal dichalcogenides (ReS₂, NbS₂, n-type WSe₂, MoS₂, p-type MoSe₂, TaS₂) hexagonal BN (hBN) and graphene were determined using atomic force microscope with conducting silicon tip in dark and under illumination to identify material for integrated optical sensor in NEMS/MEMS switches. In all cases the surface adhesion forces increased under illumination. WSe₂, an indirect band gap with 1.66 eV energy, showed the largest change of ~165% in its adhesion force. Hexagonal BN, a wide band gap energy material of 5.5 eV, showed the smallest change of 7.2% comparable to changes in our control samples of 90 nm SiO₂ on Si and 100 nm Au on SiO₂/Si. NbS₂ and graphene, samples with the smallest energy band gaps, respectively showed 54.8% and 8.4% increase in surface adhesion forces under illumination.