Strain induced exciton fine-structure splitting and shift in bent ZnO microwires

Liao, Zhi-Min; Wu, Han‐Chun; Fu, Qiang; Fu, Xuewen; Zhu, Xinli; Xu, Jingyi; Shvets, I. V.; Zhang, Zhuhua; Guo, Wanlin; Leprince‐Wang, Yamin; Zhao, Qing; Wu, Xiaosong; Yu, Dapeng

doi:10.1038/srep00452

Cited by 68 publications

(84 citation statements)

References 33 publications

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“…In the bending region, the strain along the hexagonal axis [0001] varies linearly from compressive inside to tensile outside as ε = x/ρ where −d/2 ≤ x ≤ d/2, ρ is the local curvature radius, and d is the diameter of the nanowire. The maximum bending strains at the outer and inner edges of the curved nanowire are ε = ± d/2ρ [17,20], respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The elastic strain engineering becomes even more important in semiconducting micro/nano-structures because they possess much higher mechanical toughness and strength compared to their bulk counterparts [13,14]. For example, significant energy redshifts of the near-band-edge (NBE) luminescence in uniaxial strain modulated ZnO [15] and GaAs [16] nanowires, as well as in curved ZnO [17][18][19][20] and CdS [21] micro/nanowires have been observed. It has also been reported that the elastic strain-gradient can effectively modulate the photoexcited carrier and exciton dynamics in MoS 2 atomic membrane [7,22] and ZnO micro/ nanowires [23,24].…”

Section: Introductionmentioning

confidence: 96%

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Outermost tensile strain dominated exciton emission in bending CdSe nanowires

Liao

et al. 2014

Sci. China Mater.

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Artificial modulation of electronic structures and control of the transport dynamics of carriers and excitons in CdSe nanowire are important for its application in optoelectronic nanodevices. Here, we demonstrate the aggregative flow of excitons by bending CdSe nanowires. The bending strain induces spatial variance of bandgap, and the energy bandgap gradient will result in the flow of excitons towards the bending outer edge of CdSe nanowire. The exciton emission energy shows a uniform redshift in the bending region due to the aggregative flow of excitons, and the energy redshift increases linearly with increasing the strain at the outer edge of the CdSe nanowire. Our results show an effective method to drive, concentrate, and utilize the excitons in CdSe nanowires, which provides a guide for the design of high performance and flexible optoelectronic nanodevices.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Outermost tensile strain dominated exciton emission in bending CdSe nanowires

Liao

et al. 2014

Sci. China Mater.

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“…As the temperature increases to 300 K, the lasing wavelengths redshift as a result of the Varshni effect (i). 40 The wavelength shift per Kelvin (i.e., the slope) is much larger for the long NWs (~ 0.08 nm/K) compared to the short NWs (~ 0.02 nm/K). Furthermore, the phonon-mediated effects of (ii) and (iii) would be suppressed under low temperatures (e.g., experimental evidence of the narrowing of the Urbach tail width at lower temperatures is presented in the Supplementary Information Figure S10).…”

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confidence: 97%

Tailoring the Lasing Modes in Semiconductor Nanowire Cavities Using Intrinsic Self-Absorption

et al. 2013

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Understanding the optical gain and mode-selection mechanisms in semiconductor nanowire (NW) laser is key to the development of high-performance nanoscale oscillators, amplified semiconductor/plasmon lasers and single photon emitters, etc. Modification of semiconductor band structure/bandgap through electric field modulation, elemental doping or alloying semiconductors has so far gained limited success in achieving output mode tunability of the NW laser. One stifling issue is the considerable optical losses induced in the NW cavities by these extrinsic methods that limit their applicability. Herein we demonstrate a new optical self-feedback mechanism based on the intrinsic self-absorption of the gain media to achieve lowloss, room-temperature NW lasing with a high degree of mode selectivity (over 30 nm). The cadmium sulfide (CdS) NW lasing wavelength is continously tunable from 489 nm to 520 nm as the length of the NWs increases from 4 to 25 m. Our straightforward approach is widely applicable in most semiconductor or semiconductor/plasmonic NW cavities. Single crystalline semiconductor Fabry-Pé rot or whispering gallery nanowire (NW) cavity possessing naturally formed flat facets for good optical feedback is an ideal gain media for light amplification. [1][2][3][4][5][6][7][8][9][10] They are considered as one of the most important and promising routes to realizing miniaturized nanolasers and amplifiers. [11][12][13] Recent groundbreaking work on utilizing semiconductor NW cavities to compensate the damping loss and amplify the collective electron oscillations in plasmon nanocavities has kindled even greater interests in this field. 2,13,14 For practical applications, the ability to tailor the NW cavity mode is essential for developing multi-color miniaturized lasers, and critical for optimizing the resonant energy transfer between the cavity and the coupled system. 15 For a II-VI or III-V NW Fabry-Pé rot cavity, it is generally accepted that the output laser wavelength is determined by the bandgap of semiconductor NW. 11 To date, there is only limited success in tuning the optical cavity modes through (a) electric field modulation; and (b) elemental doping of the semiconductors. 6,9,16 In the former approach where the bandgap is modulated via the Franz-Keldysh or Stark effects, the NW cavities are highly susceptible to damage and only narrow tunability around 10 nm is demonstrated; 17 while in the later approach, the NW cavities are prone to structural defects induced by the dopants, thereby restricting the cavity gain. Keywords: Cadium sulfide, nanowire cavity, Urbach tail, Waveguide, lasingThough broadband tunable lasing wavelengths spanning 100 nm or more have been demonstrated in ternary semicondutor NW cavities, 18 cavity gain is however limited by the structural defects formed during the growth phase. 7,16 Use of extrinsic optical feedback such as photonic crystals to achieve better mode selectivity is another approach. However, the high-cost and complicated fabrication required, together with th...

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“…In particular, the strong electrical polarization of wurtzite semiconductors such as ZnO and GaN, arising from non-central symmetry and crystallographic polarity, has a profound effect on carrier concentration, energy band structure, photon emission energy, and excitonic behavior [1][2][3][4] . Thus, the nature of the terminating surface on wurtzite crystal, which is intimately associated with the growth direction and the bonding state, can play a crucial role in its electrical, optical, and photophysical features.…”

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confidence: 99%

Recent Progress in Synthesis of Plate-like ZnO and its Applications: A Review

Jang¹

2017

J. Korean Ceram. Soc

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ZnO is a wide band-gap semiconductor with piezoelectric properties suitable for opto-electronics, sensors, and as an electrode material. Controlling the shape and crystallography of any semiconducting nanomaterial is a key step towards extending their use in applications. Whilst anisotropic ZnO wires have been routinely fabricated, precise control over the specific surface facets and tailoring of polar and non-polar growth directions still requires significant refinement. Manipulating the surface energy of crystal facets is a generic approach for the rational design and growth of one-dimensional (1D) building blocks [1][2][3][4] . Although the surface energy is one basic factor for governing crystal nucleation and growth of anisotropic 1D structures, structural control based on surface energy minimization has not been yet demonstrated [5][6][7][8][9] . Here, we report an electronic configuration scheme to rationally modulate surface electrostatic energies for crystallographic-selective growth of ZnO wires. The facets and orientations of ZnO wires are transformed between hexagonal and rectangular/diamond cross-sections with polar and non-polar growth directions, exhibiting different optical and piezoelectrical properties. Our novel synthetic route for ZnO wire fabrication provides new opportunities for future opto-electronics, piezoelectronics, and electronics, with new topological properties.I norganic compound semiconductors with the inherent structural anisotropy continue to be of considerable interest for both fundamental science and potential technology applications due to their diverse functionalities and unique features combined with the dynamic electro-mechanical coupling and the static polarization [10][11][12][13][14] . In particular, the strong electrical polarization of wurtzite semiconductors such as ZnO and GaN, arising from non-central symmetry and crystallographic polarity, has a profound effect on carrier concentration, energy band structure, photon emission energy, and excitonic behavior [1][2][3][4] . Thus, the nature of the terminating surface on wurtzite crystal, which is intimately associated with the growth direction and the bonding state, can play a crucial role in its electrical, optical, and photophysical features. Furthermore, such anisotropic phenomena are particularly striking and relevant for one-dimensional (1D) structure due to its geometric crystal structure with the highly uniaxial anisotropy as well as the highly confined strain and polarization field, compared to bulk and film structures. Hence, tailoring facets and crystal shapes of 1D wurtzite materials through control of crystal preferred growth orientation is an effective way for achieving not only designed physical properties, but also the ability to manipulate the polarization between parallel to and perpendicular to their length. This in turn allows for creating a new concept of topological architecture and unique function pertinent to potential device applications. However, because of chemically active polar surfaces wi...

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Strain induced exciton fine-structure splitting and shift in bent ZnO microwires

Cited by 68 publications

References 33 publications

Outermost tensile strain dominated exciton emission in bending CdSe nanowires

Outermost tensile strain dominated exciton emission in bending CdSe nanowires

Tailoring the Lasing Modes in Semiconductor Nanowire Cavities Using Intrinsic Self-Absorption

Recent Progress in Synthesis of Plate-like ZnO and its Applications: A Review

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