Modeling of the Interminiband Absorption Coefficient in InGaN Quantum Dot Superlattices

The temperature dependence of Λ-graded InGaN solar cells is studied through simulation using nextnano software. Λ-Graded structures have been designed by increasing and then decreasing the indium composition in epitaxial InGaN layers. Due to polarization doping, layers of p-type and n-type doping arise without the need for impurity doping. Different individual structures are designed by varying the indium alloy profile from GaN to maximum indium concentrations, xmax, ranging from 20% to 90% pseudomorphically strained to a GaN substrate and from 20% to 100% for completely strain-relaxed materials and linearly decreases back to GaN. For InxGa1-xN with x>∼0.9, if the material is strained to the GaN lattice constant, it is predicted to have a negative band gap. So this case is not considered here. The temperature dependence of the electrical and optical properties as they relate to the solar efficiency of the Λ-graded structures under relaxed and strained conditions are studied. Additionally, the dimensionless absorption coefficients are fitted and plotted as functions of the band gap under both strained and relaxed conditions at different temperatures. As a result, the generation rates as functions of the penetration depth within a cell can be calculated in order to obtain the solar cell parameters including efficiency for each Λ-graded structure at different temperatures. Under the strained condition, the xmax, where the solar cell efficiency reaches its maximum for each temperature, decreases as the temperature increases. At the same time, under the relaxed condition, at low temperatures (T = 100–400 K), xmax is 100%, that is, grading to InN results in maximum efficiency, while at higher temperatures (T = 500–800 K), xmax decreases with the increasing temperature.

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“…The absorption coefficient for InGaN can be generally represented as follows (Brown et al, 2010;Belghouthi et al, 2015;Giannoccaro et al, 2016):…”

Section: Strain: Impact On Device Performancementioning

confidence: 99%

Modeling of temperature dependence of Λ-graded InGaN solar cells for both strained and relaxed features

Sarollahi

Zamani-Alavijeh²,

Aldawsari³

et al. 2022

Front. Mater.

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“…Furthermore, the transition probability of electrons within the conduction band is much higher than interband transitions, which involves both the valence and conduction bands 9 – 12 . Recently, the intraband absorption has been confirmed in the near- to mid-infrared spectrum using GaN/AlGaN multiple quantum well (MQWs) 12 – 18 , coupled double quantum well 19 , and GaN/AlN quantum dot (QD) 20 – 23 material systems. However, intraband absorption of transverse electric (TE) polarized light can be hardly achieved using quantum well based structures; a consequence of intraband selection rules.…”

Section: Introductionmentioning

confidence: 99%

Mid-infrared photon sensing using InGaN/GaN nanodisks via intersubband absorption

Zhang

Afroja

Kum

et al. 2022

Sci Rep

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Intersubband (intraband) transitions allow absorption of photons in the infrared spectral regime, which is essential for IR-photodetector and optical communication applications. Among various technologies, nanodisks embedded in nanowires offer a unique opportunity to be utilized in intraband devices due to the ease of tuning the fundamental parameters such as strain distribution, band energy, and confinement of the active region. Here, we show the transverse electric polarized intraband absorption using InGaN/GaN nanodisks cladded by AlGaN. Fourier transform infrared reflection (FTIR) measurement confirms absorption of normal incident in-plane transverse electric polarized photons in the mid-IR regime (wavelength of ~ 15 μm) at room temperature. The momentum matrix of the nanodisk energy states indicates electron transition from the ground state s into the px or py orbital-like excited states. Furthermore, the absorption characteristics depending on the indium composition and nanowire diameter exhibits tunability of the intraband absorption spectra within the nanodisks. We believe nanodisks embedded nanowires is a promising technology for achieving tunable detection of photons in the IR spectrum.

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“…A better understanding of the electronic, optical and thermal properties of InGaN/GaN heterostructures is necessary and has a significant impact on the physical and electrical performance of electronic components, circuits, and systems [20,21,22]. Generally, theoretical modeling and numerical simulation studies have been widely used in the photovoltaic field in order to determine the most important parameters for solar cell operation and to minimize losses and to optimize the physical and geometrical parameters in order to get maximum efficiency.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of the Electronic and Electrical Characteristics of InGaN/GaN-MQW Solar Cells

et al. 2019

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In this paper, a numerical model allows to analyze the photovoltaic parameters according to the electronic properties of InxGa1−xN/GaN MQW solar cells under the effect of temperature, the number of quantum wells and indium composition. The numerical investigation starts from the evaluation through the finite difference (FDM) simulation of the self-consistent method coupled with the photovoltaic parameters taking into account the effects of the spontaneous and piezoelectric polarization. The results found were consistent with the literature. As expected, the temperature had a negative impact on the performance of InGaN/GaN MQW solar cells. However, increasing the number of quantum wells improves cell performance. This positive impact further improves with the increase in the indium rate. The obtained results were 28 mA/cm2 for the short-circuit current density, 1.43 V for the open-circuit voltage, and the obtained conversion efficiency was 31% for a model structure based on 50-period InGaN/GaN-MQW-SC under 1-sun AM1.5G.

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Modeling of the Interminiband Absorption Coefficient in InGaN Quantum Dot Superlattices

Cited by 8 publications

References 55 publications

Modeling of temperature dependence of Λ-graded InGaN solar cells for both strained and relaxed features

Modeling of temperature dependence of Λ-graded InGaN solar cells for both strained and relaxed features

Mid-infrared photon sensing using InGaN/GaN nanodisks via intersubband absorption

Numerical Modeling of the Electronic and Electrical Characteristics of InGaN/GaN-MQW Solar Cells

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