02316nas a2200145 4500008004100000245007000041210006900111260001300180490000900193520180900202100001902011700002402030700001702054856009902071 2020 eng d00aSpectroscopic probe of atomically thin domains of CVD-grown MoSe20 aSpectroscopic probe of atomically thin domains of CVDgrown MoSe2 bAIPcNOV0 v22653 a
Since the discovery of graphene, two-dimensional Layered Transition Metal Dichalcogenides (TMDCs) such as MoS2, MoSe2, and WS2 having a tunable bandgap, have emerged as one of the most stable classes of materials making them attractive for various applications. We have investigated the growth mechanism and shape evolution of various domains of CVD-grown MoSe2 on insulating substrates by spectroscopic techniques. The different morphologies were analyzed using Raman and photoluminescence spectroscopies. The transformation from the precursor MoO3 to MoSe2 is found to depend on a number of growth parameters and experimental conditions.

 

 

1 aSingh, Vineeta1 aLate, Dattatray, J.1 aRath, Shyama uhttps://library.ncl.res.in/content/spectroscopic-probe-atomically-thin-domains-cvd-grown-mose201861nas a2200169 4500008004100000022001400041245011800055210006900173260000800242300001100250490000700261520123200268100001901500700002401519700001701543856013101560 2020 eng d a0734-210100aTunable light emission from chemical vapor deposited two-dimensional MoSe2 by layer variation and S incorporation0 aTunable light emission from chemical vapor deposited twodimensio cMAR a0234020 v383 a

Mono- and few-layer thick MoSe2 and MoSxSe2-x domains were grown on insulating SiO2/Si substrates by chemical vapor deposition. Scanning electron microscopy and optical contrast images were used to determine the domain size and morphology. The structure, crystallinity, and the thickness (number of layers) of the as-synthesized domains were determined from Raman spectroscopy. The light emission was determined from photoluminescence (PL) spectroscopy. The PL emission started appearing only in domains having four layers or less, with the intensity increasing as the number of layers decreased. The PL peak position varied between 1.48eV (similar to 838nm) for four layers to 1.55eV (similar to 800nm) in the monolayer limit. Sulfur incorporation was done to enable a further tunability of the bandgap. The monolayer bandgap changed from 1.55eV for MoSe2 to 1.64eV (similar to 756nm) for MoS0.32Se0.68. The other effect of S incorporation was the formation of larger area domains in the alloy as compared to binary MoSe2 with an improvement in the structural properties, thus providing a pathway to improve the properties of two-dimensional semiconductors by mixing of two materials with similar atomic arrangements.

1 aSingh, Vineeta1 aLate, Dattatray, J.1 aRath, Shyama uhttps://library.ncl.res.in/content/tunable-light-emission-chemical-vapor-deposited-two-dimensional-mose2-layer-variation-and-s