Optical properties of GaAs (original) (raw)

Improvement of Quantum Efficiency and Reflectance of GaAs Solar Cell Mrityunjoy Kumar Ray 1

2016

Abstract—In this work authors presented improvement performance of GaAs solar cell of antireflection coating and texturing using PC1D simulation. About 32.58 % light reflect from a bare GaAs surface and giving external quantum efficiency about 67.32%.This paper presented the improvement of external quantum efficiency (EQE) of GaAs solar cell about 14.23 % using antifriction coating (ARC) of Silicon-di-Oxide (SiO2) with refractive index 1.55 at thickness 121 nm and about 14.77 % using ARC of and Indium Tin Oxide (ITO) with refractive index 1.92 at 100 nm. The structure of SiO2/GaAs is showing reflectance about 4.370 % and the structure of ITO/GaAs is showing reflectance about 0.0087 % based on AM1.5 photon flux from 300-1200nm. Further EQE can be improved about 1.62 % using SiO2 ARC and 2.56 % using ITO ARC with deposition of 5-10 nm front surfaces texturing over ARC by texturing angle of 54.740. Combination of ARC and texture improve the reflectance about 4.36%.

Numerical Modeling of GaAs Solar Cell Performances

Electronics and Electrical Engineering, 2013

The process of modeling photovoltaic devices is a tedious task in that it depends heavily on several intrinsic and extrinsic properties of the material. In this paper, numerical solutions are obtained using the Personal Computer 1 Dimension (PC1D) software package in order to improve solar cells performance. The analysis deals with high efficiency GaAs solar cells, in order to search the technological parameters leading to optimal performances of the cells, the effects of the doping level and the thicknesses of the base and emitter layers were also investigated. The optimal fill factor and the conversion efficiency that were obtained are 86.76 % and 25.8 % respectively.

A GaAs solar cell with an efficiency of 26.2% at 1000 suns and 25.0% at 2000 suns

IEEE Transactions on Electron Devices, 2001

A GaAs solar cell without prismatic covers, with the highest efficiency known to the authors in the range of 1000-2000 suns for a single junction, is presented. Low temperature liquid phase epitaxy is used for its growth. In addition to improvements such as the achievement of a good quality material or a low contact resistance, this solar cell exhibits specific enhanced aspects. Among the most noticeable are: 1) an innovative design; 2) a double and gradual emitter layer; 3) a small size: 1 mm 2 , 4) a finger width of the front metal grid of 3 m; and 5) a tailored ARC deposition based on a nondestructive and accurate AlGaAs window layer characterization. As a consequence, an efficiency of 26.2% at 1000 suns and 25.0% at 2000 suns AM1.5D (standard conditions) is achieved thanks mainly to a short-circuit current density at 1000 suns of 26.8 A/cm 2 (and 53.6 A/cm 2 at 2000 suns) with a simultaneous series resistance of 3 m cm 2 .

OPTICAL AND TRANSPORT PROPERTIES OF p-TYPE GaAs

ABSTRACT Electrical properties such as electrical resistivity, Hall coefficient, Hall mobility, carrier concentration of p-type GaAs samples were studied at room temperature (300 K). Resistivity was found to be of the order of 5.6 × 10-3Ω-cm. The Hall coefficient (RH) was calculated to be 7.69 × 10-1cm3/C and Hall mobility (μH) was found to be 131cm2/V-s at room temperature from Hall effect measurements. Carrier concentration was estimated to be 8.12 × 1018/cm3 and the Fermi level was calculated directly from carrier density data which was 0.33 eV. Photoconductivity measurements were carried on by varying sample current, light intensity and temperature at constant chopping frequency 45.60 Hz in all the cases mentioned above. It was observed that within the range of sample current 0.1 - 0.25mA photoconductivity remains almost constant at room temperature 300K and it was found to be varying non-linearly with light intensity within the range 37 - 12780 lux. Photoconductivity was observed to be increasing linearly with temperature between 308 and 428 K. Absorption coefficient (α) of the samples has been studied with variation of wavelength (300 -2500 nm). The value of optical band gap energy was calculated between 1.34 and 1.41eV for the material from the graph of (αhν) 2 plotted against photon energy. The value of lattice parameter (a) was found to be 5.651Å by implying X-ray diffraction method (XRD).

Effect of the Doping Layer Concentration on Optical Absorption in Si δ-Doped GaAs Layer

Optics and Photonics Journal, 2012

We study in this paper the intersubband optical absorption of Si- doped GaAs layer for different applied electric fields and donors concentration. The electronic structure has been calculated by solving the Schrödinger and Poisson equations self-consistently. From our results, it is clear that the subband energies and intersubband optical absorption are quite sensitive to the applied electric field. Also our results indicate that the optical absorption depends not only on the electric field but also on the donor's concentration. The results of this work should provide useful guidance for the design of optically pumped quantum well lasers and quantum well infrared photo detectors (QWIPs).

Modeling the optical dielectric function of GaAs and AlAs: Extension of Adachi’s model

Journal of Applied Physics, 1996

Optical dielectric function model of Ozaki and Adachi ͓J. Appl. Phys. 78, 3380 ͑1995͔͒ is augmented by introducing Gaussian-like broadening function instead of Lorentzian broadening. In this way a consistent and comparatively simple analytic formula has been obtained, which accurately describes the optical dielectric function of GaAs and AlAs in a wide spectral range between 0.1 and 6 eV. The acceptance-probability-controlled simulated annealing technique was used to fit the model to experimental data.

Optical Properties of Semiconductors

Springer Series in Optical Sciences, 2018

In this chapter we present basic concepts which are relevant to link the results obtained from ellipsometry data analysis with fundamental properties of semiconductors for photovoltaic applications. The linear optical properties of semiconductors are best discussed in terms of the relationship between the dielectric function ε and the band structure.

The effect of broadening on the optical dielectric function of GaAs and AlAs

1996 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings

Optical dielectric function model of Ozaki and Adachi [J. Appl. Phys. 78, 3380 (1995)l is augmented by introducing Gaussian-like broadening function instead of Lorentzian broadening. In this way a consistent and comparatively simple analytic formula has been obtained, which accurately describes the optical dielectric function of GaAs and AlAs in a wide spectral range between 0.1 and 6 eV.