Fabrication Technologies for the On‐Chip Integration of 2D Materials

Abstract

The carrier mobilities of all the listed materials are experimental results except for those of SnSe, MoO 3 , MoSSe, WSSe, and graphdiyne that are theoretical calculated values; b) The n, k values for all the listed materials are at 1550 nm except for BP at 800 nm and h-BN at 1200 nm; c) The NLO parameters of PdSe 2 , PtSe 2 , BP, h-BN, MoO 3 , and CsPbBr 3 are at 800 nm. Those of MoS 2 and Bi 2 Te 3 are at 1060 nm. Those of other materials are at 1550 nm. In addition to third-order optical nonlinearity, strong second-order optical nonlinearity has been observed for graphene, GO, MoS 2 , WSe 2 , PdSe 2 , and h-BN, with typical χ (2) values varying from 10 -12 -10 -7 m V -1 . [33,[116][117][118][119][120] ; d) The values of n 2 and β are dependent on the film thickness, here we only provide typical values obtained from experimental measurements.

Enhanced Spectral Broadening of Femtosecond Optical Pulses in Silicon Nanowires Integrated with 2D Graphene Oxide Films

“…Next, a 1.5-μm thick silica upper cladding layer was deposited using plasma enhanced chemical vapor deposition (PECVD), followed by opening a window on it down to the BOX layer via photolithography and reactive ion etching processes. Finally, the 2D layered GO film was coated onto the SOI nanowires by using a solution-based method that enabled transfer-free and layer-by-layer film coating, as reported previously [ 45 , 46 , 47 , 48 ]. Compared to the sophisticated and cumbersome film transfer processes (e.g., manipulation with scotch tape) used for other 2D materials such as graphene and transition metal dichalcogenides (TMDCs) [ 36 , 37 , 49 ], our GO coating method shows advantages in achieving highly scalable fabrication, precise control of the layer number (i.e., film thickness, with a high resolution of ~2 nm), and conformal film attachment onto integrated devices [ 41 , 47 ].…”

Graphene oxide films integrated with nanowires and ring resonators to enhance nonlinear optics

“…Further recent theoretical work has shown that these results can be significantly improved, [42][43][44][45][46][47] aided by sophisticated integration methods. [48] This work will potentially have significant implications for on-chip microcombs and their applications. In summary, our results verify the enhanced nonlinear optical performance of nanowires, waveguides, and ring resonators achievable by incorporating 2D layered GO films.…”

Enhanced self-phase modulation in silicon nitride nanowires with integrated graphene oxide 2D films

“…A silica upper cladding was then deposited using high-density plasma-enhanced chemical vapor deposition (HDP-PECVD), followed by opening a window on it down to the top surface of the Si 3 N 4 waveguides via lithography and reactive ion etching (RIE). Finally, the 2D layered GO lm was coated onto the Si 3 N 4 waveguide by using a solutionbased method that enabled transfer-free and layer-by-layer lm coating, as reported previously [45][46][47]49].…”

“…Enhanced SPM has been demonstrated in integrated waveguides incorporating graphene [36][37][38], MoS 2 [39], WS 2 [40], and graphene oxide (GO) [41]. Amongst the different 2D materials, GO has shown many advantages for implementing hybrid integrated photonic devices with superior SPM performance, including a large Kerr nonlinearity (about 4 orders of magnitude higher than Si [42,43]), relatively low loss compared to other 2D materials (over 2 orders of magnitude lower than graphene [44,45]), facile synthesis processes [46,47], and high compatibility with CMOS fabrication [48,49]. In our previous work [41], we demonstrated enhanced SPM of picosecond optical pulses in Si waveguides integrated with 2D GO lms, achieving a maximum spectral broadening factor (BF) of ~4.3 and enhanced FOM by up to 20 times.…”