Optically Pumped Broadband Terahertz Modulator Based on Nanostructured PtSe<sub>2</sub> Thin Films

Jakhar, Alka; Kumar, Prabhat; Moudgil, Akshay; Dhyani, Veerendra; Das, Samaresh

doi:10.1002/adom.201901714

Cited by 40 publications

(24 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[25] Interestingly, PtSe 2 has no energy band-gap in the bulk form, but the band-gap increases as the thickness decreases, becoming an indirect semiconductor with a bandgap far exceeding 1 eV at the monolayer. [20,21,23,24] This significant thickness dependence originates from strong interlayer coupling, enabling various thickness-engineering-based broadband optoelectronic and photonic applications, [23] such as for photosensors, [26][27][28][29][30][31][32][33] saturable absorbers, [34][35][36] modulators, [37] and nonlinear photonic effects. [38,39] Therefore, many ultrafast spectroscopic studies have been conducted to understand photophysics in 2D PtSe 2 .…”

Section: Introductionmentioning

confidence: 99%

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe₂

Bae

Nah

Lee

et al. 2021

Small

View full text Add to dashboard Cite

semiconducting systems. [1,2] A representative example is layered 2D semiconductors, where reduced dielectric screening leads to huge exciton binding energies up to several hundreds of meV, enabling strong excitonic light-matter interactions even at room temperature. Thus, excitons in 2D materials govern fundamental optical properties such as light absorption and emission. [3,4] Furthermore, excitons in 2D systems often couple with their unique physical properties, such as a thickness-dependent change in the bandgap nature and polarization-governed optical selection rules. These relationships provide rich physics and proper functionality for novel optoelectronic applications. [3][4][5] To fully exploit the excellent properties of excitons, it is essential to explore their behavior on ultrashort timescales. Many fundamental excitonic phenomena such as recombination, many-body interactions, and scattering mechanisms occur on femtosecond or picosecond timescales. [6][7][8][9][10][11][12][13] Also, ultrafast light-matter interactions can modulate excitons, enabling novel quantum memory and switching effects. [14][15][16][17][18][19] Therefore, understanding exciton behaviors on Strongly bound excitons are a characteristic hallmark of 2D semiconductors, enabling unique light-matter interactions and novel optical applications. Platinum diselenide (PtSe 2 ) is an emerging 2D material with outstanding optical and electrical properties and excellent air stability. Bulk PtSe 2 is a semimetal, but its atomically thin form shows a semiconducting phase with the appearance of a band-gap, making one expect strongly bound 2D excitons. However, the excitons in PtSe 2 have been barely studied, either experimentally or theoretically. Here, the authors directly observe and theoretically confirm excitons and their ultrafast dynamics in mono-, bi-, and tri-layer PtSe 2 single crystals. Steady-state optical microscopy reveals exciton absorption resonances and their thickness dependence, confirmed by first-principles calculations. Ultrafast transient absorption microscopy finds that the exciton dominates the transient broadband response, resulting from strong exciton bleaching and renormalized band-gap-induced exciton shifting. The overall transient spectrum redshifts with increasing thickness as the shrinking bandgap redshifts the exciton resonance. This study provides novel insights into exciton photophysics in platinum dichalcogenides.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202103400.

show abstract

Section: Introductionmentioning

confidence: 99%

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe₂

Bae

Nah

Lee

et al. 2021

Small

View full text Add to dashboard Cite

show abstract

“…[38] To obtain this layered PtSe 2 with high crystal quality, diverse synthesis methods have been developed. [7,12,24,29,[39][40][41][42][43][44][45][46][47][48] In this section, we will introduce these methods and compare their advantages and disadvantages, providing a reference for the development and fabrication of PtSe 2 -based devices.…”

Section: Synthesis Methodsmentioning

confidence: 99%

Layered PtSe₂ for Sensing, Photonic, and (Opto‐)Electronic Applications

Wang

McEvoy

et al. 2020

Advanced Materials

View full text Add to dashboard Cite

An increasing enthusiasm for research into 2D nanostructures is driven by their exceptional mechanical, chemical, optical, and physical properties that arise from their atomically thin dimension. These properties make 2D nanostructures promising candidates for applications in the next generation of photonic, valleytronic, and (opto-)electronic devices. 2D black phosphorus, for instance, is a novel 2D material with a thickness-tunable bandgap and outstanding properties that have attracted tremendous interest. However, its commercial and industrial applications have been greatly hindered by its poor environmental stability. [1] Layered transition metal dichalcogenides (TMDs), such as MoS 2 , WS 2 , and MoSe 2 , have been experimentally demonstrated to possess thickness-dependent bandgaps and many other promising physical, chemical, and mechanical properties. However, the majority of these TMDs suffer from relatively low charge-carrier mobilities, rather large Schottky barriers when contacted with metals, complicated fabrication processes and a narrow spectral response mainly in the visible region. [2,3] As a result, even though the first report on the experimental isolation of graphene was 16 years ago, [4] and researchers worldwide have spent massive time and effort investigating 2D materials, thus far few have been effectively employed in industrial and commercial applications. Recently, layered PtSe 2 , a Group-10 TMD, has been demonstrated to be one of the most promising 2D materials for adoption by industries due to its unprecedented photonic, physical, and chemical properties along with lowtemperature synthesis methods, high charge-carrier mobilities and long-term air stability. [5-11] One of the important industrial advantages of PtSe 2 is the developed synthesis methods, some of which are compatible with modern silicon technologies. The studied methods to synthesize layered PtSe 2 include molecular-beam epitaxy (MBE), [7,12] chemical vapor deposition (CVD), [8,13] thermally assisted conversion (TAC), [14-20] chemical vapor transport (CVT), [5] plasma-assisted selenization (PAS), [21] microwave assisted synthesis (MAS), [22] mechanical exfoliation (ME), [13,23] the wet chemical (WC) method, [24,20] and so on. Both MBE and CVD are typically carried out at high temperature and can result in high-quality PtSe 2 monolayers. In contrast, wafer-scale and thickness-tunable layered PtSe 2 can be obtained using TAC Since the first experimental discovery of graphene 16 years ago, many other 2D layered nanomaterials have been reported. However, the majority of 2D nanostructures suffer from relatively complicated fabrication processes that have bottlenecked their development and their uptake by industry for practical applications. Here, the recent progress in sensing, photonic, and (opto-)electronic applications of PtSe 2 , a 2D layered material that is likely to be used in industries benefiting from its high air-stability and semiconductor-technology-compatible fabrication methods, is reviewed. The advantages and disad...

show abstract

“…Third-order NLO crystalline porous materials have found wide applications in many fields such as waveguides for all-optical switching, optical limiting and laser modulators. [47,129,130] Different from the second-order NLO, the third-order NLO is not restricted by the NCS configuration. Therefore, a wider diversity of porous materials can be adapted for third-order NLO.…”

Section: Crystalline Porous Materials For Third-order Nlomentioning

confidence: 99%

Crystalline Porous Materials for Nonlinear Optics

Shi

Han

et al. 2021

Small

View full text Add to dashboard Cite

metal chalcogenides, [17,18] graphdiyne, [19][20][21] etc.) and perovskites [22][23][24][25][26] have been in a state of vigorous development and rapid advances for applications in optoelectronics, catalysis, energy conversion, due to their autologous admirable chemistry and physics characteristics. [27,28] Porous materials, a scientifically evolving and functionally compelling class of solid compounds with well-defined pore structures, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and polyoxometalates (POMs), have attracted broad research interest because of their wide applications in many fields including, but not limited to, adsorption, separation, catalysis, and photovoltaics. [29][30][31][32] Through fine control over the organic units to create predesigned skeletons, an exceptionally large set of materials with unique porous structures and remarkable properties have been developed. [33,34] MOFs, also known as coordination polymers or coordination networks, are one class of crystalline porous materials prepared by the self-assembly of metal ions or clusters with organic ligands. [35] They have drawn tremendous research interest for their customizable chemical structures along with unique chemical and physical properties, [36][37][38][39][40][41] which guarantee their wide applications as adsorption and separation, catalysts, magnetic, and light emitting materials. [36,[42][43][44][45] The use of appropriate ligands with optimized electronic push-pull structures, the degree of conjugation in the system and the encapsulation of guest molecules with different properties are some of the effective strategies to enhance the linear and nonlinear optical properties of the MOFs materials. [46][47][48] COFs, constructed from organic moltifs linking through strong covalent bonding, are a kind of crystalline porous materials in which the atoms of organic units are precisely integrated to create periodic frameworks and nanopores. [49,50] Although the thermal stability and crystallinity of COFs are lower than MOFs, they have received wide attention due to their low density, large surface area and strong ππ stacking. [51][52][53][54] It has been appreciated that the applications of COFs materials in third-order NLO such as two-photon fluorescence have been well developed in recent years. [55][56][57] Similar to MOFs and COFs, POMs formed by the coordination of early transition metals and oxygen atoms are a class of crystalline porous materials with unique structures and properties for their exceptional crystallinity and high stability. [58] POMs are intrinsically electron deficient, and their electronaccepting capability in combination with highly delocalized π-conjugated systems is particularly promising for producing NLO materials. [59,60] The structure of all the crystalline porous Crystalline porous materials have been extensively explored for wide applications in many fields including nonlinear optics (NLO) for frequency doubling, two-photon absorption/emission, optical limiting effect,...

show abstract

Optically Pumped Broadband Terahertz Modulator Based on Nanostructured PtSe₂ Thin Films

Cited by 40 publications

References 37 publications

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe₂

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe₂

Layered PtSe₂ for Sensing, Photonic, and (Opto‐)Electronic Applications

Crystalline Porous Materials for Nonlinear Optics

Contact Info

Product

Resources

About

Optically Pumped Broadband Terahertz Modulator Based on Nanostructured PtSe2 Thin Films

Cited by 40 publications

References 37 publications

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe2

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe2

Layered PtSe2 for Sensing, Photonic, and (Opto‐)Electronic Applications

Crystalline Porous Materials for Nonlinear Optics

Contact Info

Product

Resources

About

Optically Pumped Broadband Terahertz Modulator Based on Nanostructured PtSe₂ Thin Films

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe₂

Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe₂

Layered PtSe₂ for Sensing, Photonic, and (Opto‐)Electronic Applications