arXiv subjects

Khikmat Kh. Muminov

Publications and source records attributed to Khikmat Kh. Muminov.

8 recordsLinked to original sources

arXiv2016

Simulation of the Efficiency of CdS/CIGS Tandem Multi-Junction Solar Cells Using AMPS-1D

In this paper we conduct numerical simulation of CdS/CIGS solar cells by use of the AMPS-1D software aiming to formulate the optimal design of the new multi-junction tandem solar cell providing its most efficient operation. We start with the numerical simulation of single-junction CdS/CIGS solar cells, which shows that its highest efficiency of 17.3% could be achieved by the thickness of CIGS p-layer of 200 nm. This result is in a good agreement with experimental data where the highest efficiency was 17.1% with the solar cell thickness of 1 micron. By use of the results of the numerical simulation of the single-junction solar cells we developed the design and conducted optimization of the new multi-junction tandem CdS/CIGS solar cell structure. Numerical simulation shows that the maximum efficiency of this solar cell is equal to 48.3%, which could be obtained with the thickness of the CIGS p-layer of 600 nm at a standard illumination of AM 1.5.

physics.ins-det↗

arXiv2016

Simulation of the Efficiency of CdS/CdTe Tandem Multi-Junction Solar Cells

In this paper we study CdS/CdTe solar cells by means of AMPS-1D software. First we study the effect of thickness of semiconductor layers on the output parameters of the CdS/CdTe solar cell, such as density of short-circuit current, open circuit voltage, fill factor and efficiency. Numerical simulation shows that the highest efficiency of single-junction CdS/CdTe solar cell equal to 18.3% is achieved when the CdTe layer thickness is 1000 nm and a CdS layer is 60 nm. Then, in order to obtain the maximal value of the efficiency, new tandem multi-junction structure consisting of layers of two solar cells connected with each other back to back are designed and engineered taking into account the results obtained for the single-junction solar cells. Numerical simulations show that its highest efficiency in 31.8% can be obtained when the thickness of CdS p-layer is equal to 50 nm, and the thickness of the CdS n-layer is equal to 200 nm, while thicknesses of the CdTe n-layer and CdTe p-layer are kept fixed and equal to 3000 nm and 1000 nm, respectively.

physics.ins-det↗

arXiv2016

Simulation of the Efficiency of a-SiC:H/a-Si:H Tandem Multilayer Solar Cells

In this paper we carried out theoretical study of the general issues related to the efficiency of SiC:H/a-Si:H single- and multi-junction tandem solar cells. Implementation of numerical simulations by the use of AMPS-1D program of one-dimensional analysis of microelectronic and photonic structures for the analysis of hydrogenated silicon solar cells allowed us to formulate the optimal design of new kind of multi-junction tandem solar cells, providing its most efficient operation. The numerical analysis of SiC:H/a-Si:H single-junction solar cell whith doped i-layer used as the intermediate absorbing layer (a -Si: H) placed between layers of p-type (a-SiC: H) and n-type (a-Si: H) has been conducted. It has been established that after optimizing the solar cell parameters its highest efficiency of 19.62% is achieved at 500 nm thickness of i-layer. The optimization of the newly developed multi-junction structure of a-SiC:H/a-Si:H tandem solar cell has been conducted. It has been shown numerically that its highest efficiency of 22.6% is achieved at the thickness of 270 nm of intermediate i-layer.

physics.ins-det↗

arXiv2015

Quadrupole Excitation in Tunnel Splitting Oscillation in Nano-Particle $Mn_{12}$

We analyze the interference between tunneling paths that occurs for a spin system with special Hamiltonian both for dipole and quadrupole excitation. Using an instanton approach, we find that as the strength of the second-order transverse anisotropy is increased, the tunnel splitting for both excitations are modulated, with zeros occurring periodically and the number of quenching points for quadrupole excitation decreases. This effect results from the interference of four tunneling paths connecting easy-axis spin orientations and occurs in the absence of any magnetic field.

cond-mat.other↗

arXiv2012

A Simple Classification of Solitons

In this report, fundamental educational concepts of linear and non-linear equations and solutions of nonlinear equations from the book High-Temperature Superconductivity: The Nonlinear Mechanism and Tunneling Measurements (Kluwer Academic Publishers, Dordrecht, 2002, pages 101-142) is given. There are a few ways to classify solitons. For example, there are topological and nontopological solitons. Independently of the topological nature of solitons, all solitons can be divided into two groups by taking into account their profiles: permanent and timedependent. For example, kink solitons have a permanent profile (in ideal systems), while all breathers have an internal dynamics, even, if they are static. So, their shape oscillates in time. The third way to classify the solitons is in accordance with nonlinear equations which describe their evolution. Here we discuss common properties of solitons on the basis of the four classification.

math-ph↗

arXiv2012

Semiclassical description of anisotropic magnets for spin S=1

In this paper, nonlinear equations describing one-dimensional non-Heisenberg ferromagnetic model are studied by use of generalized coherent states in a real parameterization. Also dissipative spin wave equation for dipole and quadruple branches is obtained if there is a small linear excitation from the ground state.

cond-mat.str-el↗

arXiv2011

Berry phase for coherent states in spin systems

In this paper we obtain Berry phase from Schrödinger equation. For vector states, basic kets are coherent states in real parameterization. We calculate Berry phase for spin S=1/2 and spin S=1 in SU(2) group and Berry phase for spin S=1 in SU(3) group.

math-ph↗

arXiv2011

Coherent states in real parameterization up to SU(5) and classical dynamics of spin systems

In this paper, we develop the formulation of the spin coherent state in real parameterization up to SU(5). The path integral in this representation of coherent state and its classical consequence are investigated. Using the resolution of unity of the coherent state, we derive a path integral expression for transition amplitude and in the classical limit we derive the classical equation of motion.

math-ph↗