Precise measurement of weak strain by second-harmonic generation from silicon (111) surface

Zhao, Ji-Hong; Li, Xianbin; Chen, Zhanguo; Meng, Xing; Jia, Gang

doi:10.1364/josab.30.001200

Cited by 2 publications

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References 24 publications

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“…Strain-induced second harmonic generation (SHG) has been investigated for decades [24] and has been employed to generate frequency-doubled light in centrosymmetric materials, such as silicon [25][26][27][28][29][30]. The second harmonic response in these works is typically described by a phenomenological modification of the nonlinear susceptibility of the unstrained material [31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Optical imaging of strain in two-dimensional crystals

et al. 2018

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Strain engineering is widely used in material science to tune the (opto-)electronic properties of materials and enhance the performance of devices. Two-dimensional atomic crystals are a versatile playground to study the influence of strain, as they can sustain very large deformations without breaking. Various optical techniques have been employed to probe strain in two-dimensional materials, including micro-Raman and photoluminescence spectroscopy. Here we demonstrate that optical second harmonic generation constitutes an even more powerful technique, as it allows extraction of the full strain tensor with a spatial resolution below the optical diffraction limit. Our method is based on the strain-induced modification of the nonlinear susceptibility tensor due to a photoelastic effect. Using a two-point bending technique, we determine the photoelastic tensor elements of molybdenum disulfide. Once identified, these parameters allow us to spatially image the two-dimensional strain field in an inhomogeneously strained sample.

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Section: Introductionmentioning

confidence: 99%

Optical imaging of strain in two-dimensional crystals

et al. 2018

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“…However, an asymmetric stress or an electric field can break the symmetry and induce various second-order nonlinear optical effects [5] . Stress-induced PE and second-harmonic generation (SHG) have been found recently in strained Si [6][7][8][9][10] . Local electric-field-induced (EFI) second-order nonlinear optical effects, such as EFI SHG [11,12] , EFI PE, and EFI OR [13][14][15] , were observed.…”

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confidence: 99%

Optical rectification and Pockels effect as a method to detect the properties of Si surfaces

et al. 2017

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The depth profile of electric-field-induced (EFI) optical rectification (OR) and EFI Pockels effect (PE) in a Si(110) crystal are investigated. The results show that EFI OR and PE signals are very sensitive to the electric field strength in the surface layers of the Si crystal. Theoretical formulas that include the electric field parameters and the widths of the space-charge region are presented and agreed very well with the experimental results. The experiments and simulations indicate that EFI OR and PE are potential methods for researching the surface/interface properties along the depth direction in centrosymmetric crystals such as Si.OCIS codes: 240. 4350, 190.4350, 190.4720. doi: 10.3788/COL201715.062401.Second-order nonlinear optical effects, such as optical rectification (OR) and the Pockels effect (PE), have important applications in the microelectronics industry. OR has been used for terahertz generation [1,2] , which is promising in photoelectric communication and imaging. The PE not only is a standard mechanism used in modulation devices, but also has been used for the measurement of electric signals [3,4] . In centrosymmetric materials, such as Si and Ge, OR and the PE are theoretically forbidden according to the electric-dipole approximation. However, an asymmetric stress or an electric field can break the symmetry and induce various second-order nonlinear optical effects [5] . Stress-induced PE and second-harmonic generation (SHG) have been found recently in strained Si [6][7][8][9][10] . Local electric-field-induced (EFI) second-order nonlinear optical effects, such as EFI SHG [11,12] , EFI PE, and EFI OR [13][14][15] , were observed. EFI SHG and EFI second-harmonic spectroscopy have been widely used for characterization of Si-SiO 2 interfaces in metal-oxide-semiconductor (MOS) devices [16][17][18][19][20][21][22][23][24] . In these investigations, researchers mainly focused on Si(111) or Si(001) surfaces, and there have been very few papers on the nonlinear optical effects of Si(110) surfaces. Furthermore, researchers usually applied in-plane scanning to characterize the surfaces or interfaces, especially for SHG detection [25,26] . It is well known that space-charge regions (SCRs) often exist in the surface/interface layers of Si devices. The width of the SCR and the distribution of a nonuniform electric field in the SCR are closely related to the surface/interface properties, such as surface/interface states and surface/ interface charges. Nevertheless, the in-plane scanning method cannot reveal the detailed characteristics of SCRs.In this Letter, we investigated EFI OR and the EFI PE in Si(110) surface layers. In particular, we measured and analyzed the depth profile of the EFI OR, namely, the distribution of EFI OR signals along the thickness direction of the Si(110) crystals. The EFI OR depends on the electric field and the width of the SCRs, according to the theoretical simulations. Experimental results show that EFI OR and the EFI PE are very sensitive to the surface properties and are p...

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Precise measurement of weak strain by second-harmonic generation from silicon (111) surface

Cited by 2 publications

References 24 publications

Optical imaging of strain in two-dimensional crystals

Optical imaging of strain in two-dimensional crystals

Optical rectification and Pockels effect as a method to detect the properties of Si surfaces

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