RESUMO
Homojunctions and homosuperlattices are essential structures and have been widely explored for use in advanced electronic and optoelectronic devices. However, artificially manipulating crystalline phases in two-dimensional (2D) monolayers is still challenging, especially when attempting to engineer lateral homogeneous junctions in a single monolayer of transition metal dichalcogenides (TMDs). Herein, we demonstrate a lateral homosuperlattice (MLHS) with alternating 1T and 2H domains in a 2D WS2 monolayer plane. In MLHSs, the 2H domains, which are laterally localized and isolated by potential wells, manifest junction interfaces and irradiated photoluminescence (PL) with a lateral periodic distribution in the two-dimensional plane. The studies on MLHSs here can provide further understanding of lateral homojunctions and homosuperlattices in a monolayer plane, providing an alternative route to modulate optical and electronic behaviors in TMD monolayers.
RESUMO
In the study of the joint estimation of time-frequency signature and direction of arrival (DOA) for multicomponent chirp signals, an estimation method based on spatial time-frequency distributions (STFDs) is proposed in this paper. Firstly, array signal model for multicomponent chirp signals is presented and then array processing is applied in time-frequency analysis to mitigate cross-terms. According to the results of the array processing, Hough transform is performed and the estimation of time-frequency signature is obtained. Subsequently, subspace method for DOA estimation based on STFD matrix is achieved. Simulation results demonstrate the validity of the proposed method.
