ترغب بنشر مسار تعليمي؟ اضغط هنا

Repairing atomic vacancies in single-layer MoSe2 field-effect transistor and its defect dynamics

122   0   0.0 ( 0 )
 نشر من قبل Fengqi Song
 تاريخ النشر 2016
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Here we repair the single-layer MoSe2 field-effect transistors by the EDTA processing, after which the devices room-temperature carrier mobility increases from 0.1 to over 70cm2/Vs. The atomic dynamics is constructed by the combined study of the first-principle calculation, aberration-corrected transmission electron microscopy and Raman spectroscopy. Single/double Se vacancies are revealed originally, which cause some mid-gap impurity states and localize the device carriers. They are found repaired with the result of improved electronic transport. Such a picture is confirmed by a 1.5cm-1 red shift in the Raman spectra.


قيم البحث

اقرأ أيضاً

We study field effect transistor characteristics in etched single layer MoS2 nanoribbon devices of width 50nm with ohmic contacts. We employ a SF6 dry plasma process to etch MoS2 nanoribbons using low etching (RF) power allowing very good control ove r etching rate. Transconductance measurements reveal a steep sub-threshold slope of 3.5V/dec using a global backgate. Moreover, we measure a high current density of 38 uA/um resulting in high on/off ratio of the order of 10^5. We observe mobility reaching as high as 50 cm^2/V.s with increasing source-drain bias.
72 - Saban M. Hus 2020
Non-volatile resistive switching, also known as memristor effect in two terminal devices, has emerged as one of the most important components in the ongoing development of high-density information storage, brain-inspired computing, and reconfigurable systems. Recently, the unexpected discovery of memristor effect in atomic monolayers of transitional metal dichalcogenide sandwich structures has added a new dimension of interest owing to the prospects of size scaling and the associated benefits. However, the origin of the switching mechanism in atomic sheets remains uncertain. Here, using monolayer MoS$_2$ as a model system, atomistic imaging and spectroscopy reveal that metal substitution into sulfur vacancy results in a non-volatile change in resistance. The experimental observations are corroborated by computational studies of defect structures and electronic states. These remarkable findings provide an atomistic understanding on the non-volatile switching mechanism and open a new direction in precision defect engineering, down to a single defect, for achieving optimum performance metrics including memory density, switching energy, speed, and reliability using atomic nanomaterials.
Single-layer transition metal dichalcogenides are at the center of an ever increasing research effort both in terms of fundamental physics and applications. Exciton-phonon coupling plays a key role in determining the (opto)electronic properties of th ese materials. However, the exciton-phonon coupling strength has not been measured at room temperature. Here, we develop two-dimensional micro-spectroscopy to determine exciton-phonon coupling of single-layer MoSe2. We detect beating signals as a function of waiting time T, induced by the coupling between the A exciton and the A1 optical phonon. Analysis of two-dimensional beating maps combined with simulations provides the exciton-phonon coupling. The Huang-Rhys factor of ~1 is larger than in most other inorganic semiconductor nanostructures. Our technique offers a unique tool to measure exciton-phonon coupling also in other heterogeneous semiconducting systems with a spatial resolution ~260 nm, and will provide design-relevant parameters for the development of optoelectronic devices.
Arrays of identical and individually addressable qubits lay the foundation for the creation of scalable quantum hardware such as quantum processors and repeaters. Silicon vacancy centers in diamond (SiV) offer excellent physical properties such as lo w inhomogeneous broadening, fast photon emission, and a large Debye-Waller factor, while the possibility for all-optical ultrafast manipulation and techniques to extend the spin coherence times make them very promising candidates for qubits. Here, we have developed arrays of nanopillars containing single SiV centers with high yield, and we demonstrate ultrafast all-optical complete coherent control of the state of a single SiV center. The high quality of the chemical vapor deposition (CVD) grown SiV centers provides excellent spectral stability, which allows us to coherently manipulate and quasi-resonantly read out the state of individual SiV centers on picosecond timescales using ultrafast optical pulses. This work opens new opportunities towards the creation of a scalable on-chip diamond platform for quantum information processing and scalable nanophotonics applications.
We report the fabrication of back-gated field-effect transistors (FETs) using ultra-thin, mechanically exfoliated MoSe2 flakes. The MoSe2 FETs are n-type and possess a high gate modulation, with On/Off ratios larger than 106. The devices show asymmet ric characteristics upon swapping the source and drain, a finding explained by the presence of Schottky barriers at the metal contact/MoSe2 interface. Using four-point, back-gated devices we measure the intrinsic conductivity and mobility of MoSe2 as a function of gate bias, and temperature. Samples with a room temperature mobility of ~50 cm2/V.s show a strong temperature dependence, suggesting phonons are a dominant scattering mechanism.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا