Micro and nanostructures 

About: Micro and nanostructures is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Chemistry & Engineering. It has an ISSN identifier of 2773-0123. Over the lifetime, 293 publications have been published receiving 504 citations.

Optoelectronic and magnetic properties of transition metals adsorbed Pd2Se3 monolayer

Abstract: In this article, the optical, magnetic, and electronic of pristine and transition metals (TM) adsorbed Pd 2 Se 3 were systematically researched by density functional theory. The results reveal that the most stable position of Pd 2 Se 3 monolayer adsorbed by various TM is different. The band structures of Au-, Cu- and Sc–Pd 2 Se 3 structures demonstrate nonmagnetic metal behaviour, while the Co- and Cr–Pd 2 Se 3 structures display magnetic metal properties. Meanwhile, the Ni- and Pt–Pd 2 Se 3 systems show nonmagnetic semiconductor character, and Fe- and Mn–Pd 2 Se 3 systems exhibit magnetic semiconductor features. Moreover, the work function of Au-, Cu-, Co-, Mn- and Fe–Pd 2 Se 3 structures is lower than Pd 2 Se 3 monolayer, which demonstrates that these structures have good electron emission characteristics. Interestingly, after the adsorption of TM atom, the light absorption of Pd 2 Se 3 system in various regions is boosted to varying degrees, indicating that the introduction of TM atom can improve the light absorption of Pd 2 Se 3 system in ultraviolet, visible and infrared regions. Therefore, it demonstrates that TM-Pd 2 Se 3 systems can be used to fabricate spintronic, photocatalysts and optoelectronic devices. • The most stable positions of Pd 2 Se 3 adsorbed by various TM are different. • The Ni- and Pt–Pd 2 Se 3 systems show nonmagnetic semiconductor character, and Fe- and Mn–Pd 2 Se 3 systems exhibit magnetic semiconductor. • The work function of Au-, Cu-, Co-, Mn- and Fe–Pd 2 Se 3 structures is lower than that of Pd 2 Se 3 . • The introduction of TM atom can improve the light absorption of Pd 2 Se 3 system in ultraviolet, visible and infrared regions.

Performance enhancement of (FAPbI3)1-x(MAPbBr3)x perovskite solar cell with an optimized design

Abstract: In this paper, an optimized design of (FAPbI3)1-x(MAPbBr3)x perovskite solar cell is numerically investigated using SCAPS-1D software package. A variety of potential charge transport materials are investigated. Cu2O as HTL and ZnO as ETL outperform other choices; they are therefore considered as the best candidates. The impact of the electronic properties of both ZnO/perovskite and Perovskite/Cu2O interfaces on the solar cell performance is thoroughly investigated. We discovered that appropriate values of the conduction band offset (CBO+ = 0.29) and valence band offset (VBO+ = 0.09) assure a “spike-type” band alignment at both interfaces. This choice lowers the unwanted interfacial recombination mechanism, resulting in a challenging PCE. In addition, the impact of the work function of back contact is also investigated. According to simulation findings, Ni back electrodes with a work function of 5.04 eV is appropriate for Zn0.8Mg0.2O/(FAPbI3)0.85(MAPbB3)0.15/Cu2O perovskite solar cell. The optimized FTO/MgZnO/(FAPbI3)0.85(MAPbBr3)0.15/Cu2O/Ni PSC reaches a conversion efficiency as high as 25.86%. These findings will pave the way for the design of low-cost, high-efficiency solar cells.

Broadband polarization insensitive and tunable terahertz metamaterial perfect absorber based on the graphene disk and square ribbon

Abstract: Designing broadband absorbers with only one metamaterial layer operating in the terahertz band is a relatively difficult challenge. In this paper, we proposed and investigate a broadband metamaterial perfect absorber (MPA) based on the graphene disk and square ribbon. The conductive substrate of this structure is made of gold and the middle dielectric layer of this structure is made of Rogers RT5880LZ, which acts as a spacer layer between the gold and graphene layers. This structure, while having only one metamaterial layer, also has the advantage of easy implementation because the graphene embedded on the dielectric surface does not have a complex design. The simulation results show that the proposed absorber can provide absorption above 90% with a bandwidth of 2.173 ​THz (1.482–3.655 ​THz). The fractional bandwidth ratio of the proposed structure is 85% for absorption greater than 90%. The absorption mechanism of this structure based on electric fields has been investigated. Since the design of the proposed broadband MPA is symmetrical, this structure is not sensitive to polarization and has a good bearing angle in the range of 0–30°. The proposed structure is tunable because we can shift the absorption frequency by changing the Fermi level of graphene (μ c ). The proposed absorber with these properties is suitable and flexible for applications such as sensing, imaging, and spectroscopy. • The structure has the advantage of easy execution due to its single-layer metamaterial and simple design. • The bandwidth of the structure for absorption above 90% is equal to 2.173 ​THz (1.482–3.655 ​THz). • The structure is tunable without the need for structural changes. • The structure has behaviors such as insensitivity to polarization and high tolerance to the incident angle. • The structure is suitable for applications such as sensing, imaging and spectroscopy.

The effects of temperature and pressure on the optical properties of a donor impurity in (In,Ga)N/GaN multilayer cylindrical quantum dots

Abstract: This paper examines the variation of the linear, third-order nonlinear and total intersubband optical absorption (refractive index changes) coefficients of a donor impurity in multilayer cylindrical quantum dots (MCQDs), under the effect of temperature T and hydrostatic pressure P . Moreover, in this study, we also examined the effect of structure parameters on the optical absorption coefficients of the system. The Schrödinger equation describing the system is solved numerically by the finite element method (FEM) within the effective mass approximation. In our calculations, the confinement potential is modeled by a parabolic form in the radial direction and a square one in the z -direction. The optical absorption coefficients and refractive index changes have been investigated versus the quantum dot radius, indium composition and intensity of the incident electromagnetic for three allowed transitions: 1 s - 1 p , 2 s - 1 p and 1 p - 1 d . Our essential outcomes exhibit that the optical absorption coefficients and refractive index changes are strongly sensitive to the variation of quantum dot sizes, which enhance and blueshift as the quantum confinement is strong. On the contrary, the optical absorption coefficients and refractive index changes diminish and redshift as the quantum confinement reduces. • The optical absorption coefficients (ACs) and refractive index changes (RICs) diminish and redshift as the quantum confinement reduces. • The temperature effect reduces the electronic confinement, consequently, the optical ACs and RICs shift to lower energies (red-shift). • The hydrostatic pressure reflects an additional confinement, which makes the ACs and RICs blueshifted.

Performance enhancement of CIGS solar cell with two dimensional MoS2 hole transport layer

Abstract: This paper describes a performance analysis of solar cell based on Cu (In 1-x Ga x )Se 2 (CIGS) material as an absorber layer together with two dimensional (2d)-MoS 2 as hole transport layer (HTL) inserted between absorber layer and back contact using 1D-SCAPS program tool. In this work, numerical modeling tool has used to investigate the effect of thickness, doping concentration and defect variation on the performance of solar cell. Based on optimization of the device parameters, highest power conversion efficiency ( P C E ) of 26.81% ( V o c =0.783 V, J s c = 40.30 mA/cm 2 and F F = 84.97%), has been obtained for ZnO/CdS/CIGS/MoS 2 photovoltaic cell having 1.18eV energy bandgap ( E g ) of CIGS layer. Performance of proposed CIGS solar cell with 2d-MoS 2 HTL is better than the conventional CIGS solar cell and provide new path for recent advanced research for fabrication of solar cell on this technology. Further, solar cell's performance has been analyzed for various series-shunt resistances, work function of metal contacts and temperature for better analysis of the cell. • Optimization of thickness, doping concentration and defect density of CIGS absorber layer. • Power conversion efficiency of proposeddevice ZnO/CdS/CIGS/MoS 2 obtained 26.81%. • Design a cost-effective and thin film CIGS solar cell. • Work function of front and back contact analyzed. • Performance study at various operating temperature and series-shunt resistance.