STUDY OF POTASSIUM INTERCALATION IN TO THE GRAPHENE/MoS STRUCTURE

Используя современные расчеты из первых принципов, в данной работе мы систематически изучали интеркаляцию атомов калия в гибридную двухслойную структуру графене/ MoS. В ходе исследования были определенны концентрации атомов калия при которых энергия формирования является отрицательной. Так в частности при концентрации атомов калия, по отношению к атомам молибдена, не более x = 0,43 формирование слоя атомов калия между слоями графен/ MoS является энергетически выгодным. Начиная с концентрации атомов калия x > 0,75 наблюдается увеличение расстояние между слоями графен и MoS, что в дальнейшем приводит к разрушению структуры. Расчет зарядов показал, что атом калия при небольших концентрациях отдает примерно 0,8 - 0,85 электрона, 0,35 из которых перетекает на атомы углерода, а 0,4 - 0,5 перетекает на дисульфид молибдена. Расчёт разность электронных плотностей показал, что связь между слоями графена, дисульфид молибдена и калия имеет ковалентный характер. Using modern ab-initio calculations, in this work, we systematically studied the intercalation of potassium atoms into a hybrid two-layer graphene/MoS structure. In the course of the study, concentrations of potassium atoms were determined at which the formation energy is negative. So, in particular, when the concentration of potassium atoms (in relation to molybdenum atoms) is not more than x = 0,43, formation of a layer of potassium atoms between the graphene/ MoS layers is energetically favorable. Beginning with the concentration of potassium atoms x > 0,75 , an increase in the distance between the graphene and MoS layers is observed, which further leads to destruction of the structure. Calculation of charges showed that a potassium atom at low concentrations gives up about 0,8 - 0,85 electrons, 0,35 of which flow on carbon atoms, and 0,4 - 0,5 to molybdenum disulfide. Calculation of the difference in electron densities showed that the bond between the layers of graphene, molybdenum and potassium disulfide has a covalent nature.

Enhancement of Responsivity in Solar-Blind UV Detector With Back-Gate MOS Structure Fabricated on β-Ga2O3 Films

Monoclinic Ga2O3 (β-Ga2O3) films were grown on Si/SiO2 by using MOCVD. Then, we fabricated the solar-blind photodetector with a back-gate MOS structure. The device exhibited obvious photoresponse under 254-nm UV light illumination, and the photocurrent increased by five orders of magnitude, which could be controlled by VGS. The current generated under dark conditions could also be regulated by VGS and tended to constant when the regulation of VGS was reaching saturation. Meanwhile, VGS was confirmed to have a certain ability to regulate the photocurrent. The present device demonstrated excellent stability and fast response (rise) and recovery (decay) times under the 254-nm light illumination as well as a responsivity of 417.5 A/W, suggesting a valuable application in solar-blind UV photodetectors.

Research Of The Boundary Of The Section Of A Photo Receiver Based On Mos pCdTe / CdO Structures

In this work, we investigated an intermediate layer in the structure of a photosensitive MOS structure nCdO / pCdTe . X-ray phase analysis shows that the intermediate layer between Mo and pCdTe is rather complex in composition. It contains dichalcogenides - three oxide MoO3 and a thin layer of a composite material with the composition of ditelluride MoTe2 . According to X-ray diffraction measurements, the total thickness of the intermediate layer is no more than ~ 200Ǻ. It was shown that in the nCdO / pCdTe structure the base material CdTe mainly consists of a homogeneous cubic modification layer.