The study of flexible emission and photoconductivity in 2D layered InSe toward an applicable 1000-nm light emitter and absorber

Chuang, Ching-An; Lin, Min-Han; Yeh, Bo-Xian; Chu, Yun-Ju; Ho, Ching‐Hwa

doi:10.1007/s00339-017-0843-3

Cited by 9 publications

(6 citation statements)

References 15 publications

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“…Two major peaks obtained at 176 and 225 cm −1 are consistent with the E″ and A 1 ′ modes for the 2H phase InSe, respectively. 37,38 Two minor features observed at 198 and 237 ± 3 cm −1 are attributed to the A 2 ″(LO) and second-order A 1 ′ modes, respectively. By the curve fitting, the full width at half-maximum values of the two major Raman peaks are 10.2 (E″) and 8.2 (A 1 ′) cm −1 .…”

Section: Resultsmentioning

confidence: 99%

Ultraefficient Ultraviolet and Visible Light Sensing and Ohmic Contacts in High-Mobility InSe Nanoflake Photodetectors Fabricated by the Focused Ion Beam Technique

Yang

Hsieh

Chen

et al. 2018

ACS Appl. Mater. Interfaces

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A photodetector using a two-dimensional (2D) low-direct band gap indium selenide (InSe) nanostructure fabricated by the focused ion beam (FIB) technique has been investigated. The FIB-fabricated InSe photodetectors with a low contact resistance exhibit record high responsivity and detectivity to the ultraviolet and visible lights. The optimal responsivity and detectivity up to 1.8 × 10 A W and 1.1 × 10 Jones, respectively, are much higher than those of the other 2D material-based photoconductors and phototransistors. Moreover, the inherent photoconductivity (PC) quantified by the value of normalized gain has also been discussed and compared. By excluding the contribution of artificial parameters, the InSe nanoflakes exhibit an ultrahigh normalized gain of 3.2 cm V, which is several orders of magnitude higher than those of MoS, GaS, and other layer material nanostructures. A high electron mobility at room temperature reaching 450 cm V s has been confirmed to be one of the major causes of the inherent superior PC in the InSe nanoflakes. The oxygen-sensitized PC mechanism that enhances carrier lifetime and carrier collection efficiency has also been proposed. This work demonstrates the devices fabricated by the FIB technique using InSe nanostructures for highly efficient broad-band optical sensing and light harvesting, which is critical for development of the 2D material-based ultrathin flexible optoelectronics.

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Section: Resultsmentioning

confidence: 99%

Ultraefficient Ultraviolet and Visible Light Sensing and Ohmic Contacts in High-Mobility InSe Nanoflake Photodetectors Fabricated by the Focused Ion Beam Technique

Yang

Hsieh

Chen

et al. 2018

ACS Appl. Mater. Interfaces

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“…The X feature is tentatively assigned to be associated with a deep ingap trap level which will be discussed in detail as below. Based on the previously reported PL studies [27][28][29][30], the L feature should be related to the bound shallow donor or acceptor state transition near P z orbital band edge, for which the strict optical transition selection rule for P z orbital can be relaxed owing to the bound carrier transitions of shallow donor or acceptor states. The PL spectroscopy of InSe flakes at RT is also measured, as shown in figure 1(d).…”

Section: Resultsmentioning

confidence: 99%

“…Since the electron-impurity and electron-defects scatterings are most likely present in our InSe flakes, the estimated electron-phonon coupling constant may differ from the real value. It is also noted that, the previously reported PL feature of InSe flakes was generally associated with impurities or defects [27,28,30]. The existing electron-impurity and electron-defects scatterings can largely affect the measured relaxation time so that the estimated electron-phonon coupling constant by only considering electron-phonon coupling becomes unreliable.…”

Section: Srhmentioning

confidence: 97%

“…A comprehensive optical study associated with E xy -band transition is thus necessary, since the normal incidence is common approach in optical applications. There have been a few low-temperature PL studies reported for InSe [17,19,27,28], for instance, the emission associated with the deeper valence band in monolayer InSe was found at ∼2.9 eV [17], and the PL response near 1.25 eV, corresponding to P z orbital band edge, was found to be associated with the direct free exciton recombination, the defect related bound exciton recombination, the impurity-band as well as the donor-acceptor pair complex transitions so on [27][28][29][30]. The energy position of the main PL peak was found to exhibit only a slight variation when decreasing temperature from RT to 5 K, since the recombining carriers are bound to the native donors and acceptors at low temperatures [28].…”

Section: Introductionmentioning

confidence: 97%

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Photo-excited carrier relaxation dynamics in two-dimensional InSe flakes

Liu

Yuan

et al. 2019

Nanotechnology

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Carrier relaxation dynamics of InSe flakes is investigated by using time-resolved pump-probe reflectivity measurement. The photocarriers associated with the Pxy orbital band-edge transition at 2.40 eV, which is coupled to the in-plane polarized light, is observed to possess a lifetime of ∼19 ps at room temperature and ∼99 ps at 10 K. The temperature and power dependent carrier lifetime suggests that Shockley–Read–Hall process is the dominant nonradiative recombination mechanism responsible for the carrier relaxation. In addition, the electron scattering with a 14.5 meV optical phonon plays an active role in the carrier relaxation with increasing temperatures. A broad absorption around 1.65–1.90 eV is observed. The photocarriers associated with this broad transition show a long lifetime of ∼200 ps that is nearly independent of temperature and photon energy. This is indicative of bound carriers by defects. Our experimental results provide essential information for the characteristics of carrier dynamics and defects in InSe flakes. The experimental findings are fundamentally important for further development of microelectronics and optoelectronics based on InSe.

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“…The value of the IF here larger than 2 may be caused by the existence of In or Se vacancies in InSe. [21,33] To understand whether the increased I d -V d forward current is because of graphene preventing carrier recombination between BP and InSe, we studied the excitation and recombination dynamics of BP, InSe, and the BP/G/InSe heterostructure using femtosecond-resolved transient absorption (TA) microspectroscopy (Figures S8 and S9, Supporting Information). [34][35][36] TA spectra for InSe showed an ultrafast photoinduced absorption (PIA) between 570 and 720 nm (Figure 2a) while BP displayed both PIA at 540-560 nm and photoinduced bleaching (PIB) at 520-530 nm (Figure 2b).…”

Section: Resultsmentioning

confidence: 99%

Repression of Interlayer Recombination by Graphene Generates a Sensitive Nanostructured 2D vdW Heterostructure Based Photodetector

Wang¹,

Gao²,

Zhang³

et al. 2021

Advanced Science

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Great success in 2D van der Waals (vdW) heterostructures based photodetectors is obtained owing to the unique electronic and optoelectronic properties of 2D materials. Performance of photodetectors based 2D vdW heterojunctions at atomic scale is more sensitive to the nanointerface of the heterojunction than conventional bulk heterojunction. Here, a nanoengineered heterostructure for the first‐time demonstration of a nanointerface using an inserted graphene layer between black phosphorus (BP) and InSe which inhibits interlayer recombination and greatly improves photodetection performances is presented. In addition, a transition of the transport characteristics of the device is induced by graphene, from diffusion motion of minority carriers to drift motion of majority carriers. These two reasons together with an internal photoemission effect make the BP/G/InSe‐based photodetector have ultrahigh specific detectivity at room temperature. The results demonstrate that high‐performance vdW heterostructure photodetectors can be achieved through simple structural manipulation of the heterojunction interface on nanoscale.

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The study of flexible emission and photoconductivity in 2D layered InSe toward an applicable 1000-nm light emitter and absorber

Cited by 9 publications

References 15 publications

Ultraefficient Ultraviolet and Visible Light Sensing and Ohmic Contacts in High-Mobility InSe Nanoflake Photodetectors Fabricated by the Focused Ion Beam Technique

Ultraefficient Ultraviolet and Visible Light Sensing and Ohmic Contacts in High-Mobility InSe Nanoflake Photodetectors Fabricated by the Focused Ion Beam Technique

Photo-excited carrier relaxation dynamics in two-dimensional InSe flakes

Repression of Interlayer Recombination by Graphene Generates a Sensitive Nanostructured 2D vdW Heterostructure Based Photodetector

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