Hafnium Sulfide Nanosheets for Ultrafast Photonic Device

Abstract

in the field of ultrafast photonics. Since the successful demonstration of graphene-based saturable absorber (SA) for ultrafast pulsed lasers, [7,8] 2D layered materials including black phosphorus, topological insulators, and transition metal dichalcogenides (TMDs), have recently been extensively investigated in nonlinear optical devices for the generation of ultrafast pulses via passive modelocking operation. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] In particular, the recent advancements in the development of TMDs with unique electronic and optical attributes have explored many potential applications in electronics and photonics. [24,25] The TMDs with layered structure can be exfoliated into atomic-thin layers, which advance the development of wider applications as high-performance transistors, photodetectors and nonlinear optical devices owing to their widespread bandgaps from the visible to the nearinfrared region. [24][25][26][27][28][29][30][31] Currently, nonlinear optical devices based on group VIB TMDs have been fully studied using as saturable absorbers (SA) for the successful generation of short pulses in broadband region. [17][18][19][20][21][22][23][32][33][34][35][36] Despite the previous efforts, it is still possible to optimize the SA devices toward ultrafast photonics for the admired purposes of generating laser pulse with shorter pulse width and greater output power, which can be anticipated by exploring other members of TMDs. In comparison with intensively studied group VIB TMDs, group IVB TMDs which are theoretically predicted to have superior physical properties to group VIB TMDs, have rarely been investigated yet. [37,38] For instance, single-layered HfS 2 is expected to possess much higher carrier mobility (≈1800 cm 2 V −1 s −1 ) and smaller bandgap (≈1.2 eV) than that of MoS 2 . [38,39] Owing to superior electronic properties, ultrathin HfS 2 fabricated by mechanically exfoliation or chemical vapor deposition methods presents significant potential in phototransistors and field-effect transistors. [40][41][42][43][44][45][46][47] However, to our knowledge, the nonlinear optical properties of HfS 2 and its application in ultrafast photonics remain unknown.In this contribution, we demonstrate a new function of multilayered HfS 2 nanosheets (NSs) with nonlinear optical absorption for development of ultrafast photonic devices. We prepared HfS 2 NSs via a modified liquid exfoliation approach using isopropanol (IPA) as solvent. HfS 2 dispersions are precisely deposited onto a microfiber to form a SA device by using a photonic crystal fiber (PCF) assisted deposition method. The HfS 2 SA device is found to show excellent nonlinear absorption Group IVB transition metal dichalcogenides (TMDs) have attracted significant interests in photoelectronics due to their predictable superior physical properties compared to group VIB (Mo and W) TMDs. However, the nonlinear optical properties and ultrafast photonic devices based on group IVB TMDs remained unexplored so far. Herein, the nonlinear ...

2D Layered Materials: Synthesis, Nonlinear Optical Properties, and Device Applications

“…Driven by these efforts, mode‐locked fiber lasers based on other layered TMDCs and their derivatives including MoSe 2 , MoTe 2 , WTe 2 , WSe 2 , MoSe 2 , SnS 2 , ReS 2 , In 2 Se 3 , InS, TiS 2 , PtS 2 , PtSe 2 , and HfS 2 , have also developed rapidly, as shown in Table . It can be seen that for these lasers, the minimum pulse width is 67 fs, maximum output power is 212 mW, and maximum repetition rate is 8.82 GHz .…”

Nonlinear Optical Properties of Emerging Nano‐ and Microcrystalline Materials

“…Recently, ultrathin HfS 2 , a new member of group IVB (currently called IUPAC group 4) transition metal dichalcogenides, fabricated by mechanical exfoliation or chemical vapor deposition methods was demonstrated to possess nonlinear optical properties as a saturable absorber with saturation intensity about 8 MW cm −2 . [114] Stable pulse train with pulse duration of 222 fs at 1562 nm was achieved in the mode-locking technique. The modulation depth (15.7%) obtainable in HfS 2 nanosheets is higher than that in other 2D materials except WSe 2 and Bi 2 Te 3 .…”

Influence of Mn, Fe, Co, and Cu Doping on the Photoelectric Properties of 1T HfS2 Crystals

“…Li et al used exfoliated HfS 2 nanosheets to manufacture memory devices, which exhibited typical bipolar resistive switching behavior with a high switching voltage and a small ratio of high and low resistive states [ 29 ]. Yin et al showed that HfS 2 nanosheets exhibit excellent nonlinear optical absorption in broadband and have the potential for applications in ultrafast photonics [ 30 ]. Hoat et al utilized density functional theory to theoretically investigate the electronic structure and optical properties of HfS 2 monolayers under vertical strain.…”