The research field of two dimensional (2D) materials strongly relies on optical microscopy characterization tools to identify atomically thin materials and to determine their number of layers. Moreover, optical microscopy-based techniques opened the door to study the optical properties of these nanomaterials. We presented a comprehensive study of the differential reflectance spectra of 2D semiconducting transition metal dichalcogenides (TMDCs), MoS2, MoSe2, WS2, and WSe2, with thickness ranging from one layer up to six layers. We analyzed the thickness-dependent energy of the different excitonic features, indicating the change in the band structure of the different TMDC materials with the number of layers. Our work provided a route to employ differential reflectance spectroscopy for determining the number of layers of MoS2, MoSe2, WS2, and WSe2.

Optical spectroscopy techniques such as differential reflectance and transmittance have proven to be very powerful techniques to study 2D materials. However, a thorough description of the experimental setups needed to carry out these measurements is lacking in the literature. We describe a versatile optical microscope setup to carry out differential reflectance and transmittance spectroscopy in 2D materials with a lateral resolution of ~1 µm in the visible and near-infrared part of the spectrum. We demonstrate the potential of the presented setup to determine the number of layers of 2D materials and to characterize their fundamental optical properties such as excitonic resonances. We illustrate its performance by studying mechanically exfoliated and chemical vapor-deposited transition metal dichalcogenide samples.The use of optical microscopy based characterization techniques has been strongly bound to the born and growth of the field of 2D materials.[1-5] These techniques are widely used since they are fast and simple to implement and, very importantly, they are non-destructive. Quantitative studies of the optical contrast of flakes deposited on SiO 2 /Si substrates have been firstly used to provide a coarse estimation of the thickness This is the post-peer reviewed version of the following article: R. Frisenda et al. "Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials" Journal of Physics D: Applied Physics (2016) Special issue on 2D materials and electronic devices This is the post-peer reviewed version of the following article: R. Frisenda et al. "Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials" Journal of Physics D: Applied Physics (2016) Special issue on 2D materials and electronic devices This is the post-peer reviewed version of the following article: R. Frisenda et al. "Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials" Journal of Physics D: Applied Physics (2016) Special issue on 2D materials and electronic devices This is the post-peer reviewed version of the following article: R. Frisenda et al. "Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials" Journal of Physics D: Applied Physics (2016) Special issue on 2D materials and electronic devices This is the post-peer reviewed version of the following article: R. Frisenda et al. "Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials" Journal of Physics D: Applied Physics (2016) Special issue on 2D materials and electronic devices This is the post-peer reviewed version of the following article: R. Frisenda et al. "Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials" Journal of Physics D: Applied Physics (2016) Special issue on 2D materials and electronic devices This is the post-peer reviewed version of the followi...

Gallium selenide (GaSe) is a novel 2D material, which belongs to the layered III-VIA semiconductors family and attracted interest recently as it displays single-photon emitters at room temperature and strong optical nonlinearity. Nonetheless, few-layer GaSe is not stable under ambient conditions and it tends to degrade over time. Here atomic force microscopy, Raman spectroscopy, and optoelectronic measurements are combined in photodetectors based on thin GaSe to study its long-term stability. It is found that the GaSe flakes exposed to air tend to decompose forming first amorphous selenium and Ga 2 Se 3 and subsequently Ga 2 O 3 . While the first stage is accompanied by an increase in photocurrent, in the second stage, a decrease in photocurrent is observed, which leads to the final failure of GaSe photodetectors. Additionally, it is found that the encapsulation of the GaSe photodetectors with hexagonal boron nitride (h-BN) can protect the GaSe from degradation and can help to achieve long-term stability of the devices.

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Intratracheal injection of manganese superoxide dismutaseplasmid/liposome (MnSOD-PL) complexes has been demonstrated to delay the onset and reduce the extent of ionizing irradiation-induced murine pulmonary organizing alveolitis/ fibrosis. To facilitate translation of this modality to clinical fractionated radiotherapy, inhalation delivery of MnSOD-PL was developed using an ultrasonic nebulizer. Transgene product was quantitated by immunohistochemical quantitation and pulmonary tissue levels of MnSOD biochemical activity. C57BL/6NHsd female mice demonstrated a plasmid dose-dependent increased expression of MnSOD transgene product over the range of 250 mg-2.5 mg of MnSOD-PL administered over a constant 5 min interval. Delivery of a constant concentration of 500 mg of MnSOD-PL with varying times of administration ranging from 0.5 to 10 min demonstrated optimal MnSOD expression at 5 min. Mice pretreated by inhalation delivery of MnSOD-PL demonstrated significantly improved survival after 20 Gy single fraction irradiation to both lungs compared to LacZ-PL inhalation-treated or irradiated control mice. Mice receiving 10 fractions of 3.5 cGy demonstrated increased pulmonary MnSOD transgene product activity by a protocol of every Monday-Wednesday or daily inhalation of MnSOD-PL. Thus, inhalation radioprotective gene therapy using MnSOD-PL provides a practical and effective method for delivery of lung-specific radioprotection during fractionated radiotherapy protocols in a mouse model. Gene Therapy (2005) 12, 685-693.

This study addresses the hypothesis that altered expression of oestrogen receptor-beta and/or altered relative expression of coactivators and corepressors of oestrogen receptors are associated with and may be mechanisms of de novo tamoxifen resistance in oestrogen receptor positive breast cancer. All cases were oestrogen receptor +, node negative, primary breast tumours from patients who later had no disease progression (tamoxifen sensitive) or whose disease progressed while on tamoxifen (tamoxifen resistant). Using an antibody to oestrogen receptor-beta that detects multiple forms of this protein (total) but not an antibody that detects only full-length oestrogen receptor-beta 1, it was found that high total oestrogen receptor beta protein expressors were more frequently observed in tamoxifen sensitive tumours than resistant tumours (Fisher's exact test, P=0.046). However, no significant differences in the relative expression of oestrogen receptor b2, oestrogen receptor b5 and full-length oestrogen receptor b1 RNA in the tamoxifen sensitive and resistant groups were found. Also, when the relative expression of two known coactivators, steroid receptor RNA activator and amplified in breast cancer 1 RNA to the known corepressor, repressor of oestrogen receptor activity RNA, was examined, no significant differences between the tamoxifen sensitive and resistant groups were found. Altogether, there is little evidence for altered coregulators expression in breast tumours that are de novo tamoxifen resistant. However, our data provide preliminary evidence that the expression of oestrogen receptor b protein isoforms may differ in primary tumours of breast cancer patients who prove to have differential sensitivity to tamoxifen therapy.

polarization-sensitive photodetectors and polarimeters. [6] Up to now, however, most of the reported works on photodetectors based on 2D semiconductors are focused on transition metal dichalcogenides or other chalcogenides with marked in-plane isotropic properties and thus the built-up photodetectors are insensitive to polarized light. [3a,7] The amount of works exploring the use of dichroic 2D semiconductors is still scarce and they are mostly limited to devices with low detectivity values or with a limited cut-off wavelength. [8] Recently, Island et al. have fabricated photodetectors using TiS 3 , [7c] a member of the trichalcogenide family that presents remarkable quasi-1D electrical and optical properties with an anisotropy larger than the one of black phosphorus. [9] However, this strong in-plane anisotropy has not been exploited yet to fabricate polarization-sensitive photodetectors.Here, we demonstrate the fabrication of monolithic polarizationsensitive photodetectors based on TiS 3 . The devices are built up by staking a TiS 3 ribbon onto p-type silicon, thus forming a p-n junction based photodiode geometry which allows one to operate the device either in photovoltaic (PV) mode, without applying any external bias, or in photoconductive (PC) mode, with a positive or negative bias applied to the device. In PV mode upon illumination, the built-in electric field present at the interface between TiS 3 and Si separates the photogenerated charge carriers yielding to photocurrent even under unbiased condition. The fabricated devices show broadband photoresponse from 405 to 1050 nm and a strong dependence of their photoresponse on the polarization The capability to detect the polarization state of light is crucial in many daylife applications and scientific disciplines. Novel anisotropic 2D materials such as TiS 3 combine polarization sensitivity, given by the in-plane optical anisotropy, with excellent electrical properties. Here, the fabrication of a monolithic polarization-sensitive broadband photodetector based on a mixed-dimensionality TiS 3 /Si p-n junction is demonstrated. The fabricated devices show broadband responsivity up to 1050 nm, a strong sensitivity to linearly polarized illumination with difference between the two orthogonal polarization states up to 350%, and a good detectivity and fast response time. The discussed devices can be used as building blocks to fabricate more complex polarization-sensitive systems such as polarimeters.

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