Solar Cells, Thermophotovoltaics, and Nonlinear Devices Based on Quantum Wells

2020 ◽  
pp. 585-616
Author(s):  
Vurgaftman Igor
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Quantum Wells ◽  
Quantum Cascade Lasers ◽  
Second Harmonic ◽  
Difference Frequency ◽  
Intersubband Transitions ◽  
Intermediate Band ◽  
Nonlinear Devices ◽  
Frequency Mixing

This chapter describes the basic principles behind the solar-cell operation using both an empirical picture and fundamental thermodynamic relationships. It considers how semiconductor materials are selected for use in solar cells and why materials with different gaps need to be stacked to improve the conversion efficiency. It also discusses advanced solar-cell concepts such as quantum-well, intermediate-band, and hot-carrier solar cells. Thermophotovoltaic devices that are similar to solar cells, but designed for emission peaks at much lower effective temperatures than the surface of the sun (and narrower gaps), are also discussed, and multistage thermophotovoltaic devices are described in detail. The chapter concludes by presenting the basic nonlinear physics of intersubband transitions in quantum wells, and how to take advantage of these physical principles for second-harmonic generation and difference-frequency mixing. The important application of generating THz emission from mid-IR quantum cascade lasers using difference-frequency mixing is emphasized.

Investigation of Quantum Dot Solar Cell Device Performance

2013 ◽  
Vol 1551 ◽  
pp. 137-142
Author(s):  
Neil S. Beattie ◽  
Guillaume Zoppi ◽  
Ian Farrer ◽  
Patrick See ◽  
Robert W. Miles ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Solar Cell ◽  
Quantum Dot ◽  
Band Gap ◽  
Control Device ◽  
Open Circuit ◽  
Device Performance ◽  
Intermediate Band ◽  
Control Devices

ABSTRACTThe device performance of GaAs p-i-n solar cells containing stacked layers of self-assembled InAs quantum dots is investigated. The solar cells demonstrate enhanced external quantum efficiency below the GaAs band gap relative to a control device without quantum dots. This is attributed to the capture of sub-band gap photons by the quantum dots. Analysis of the current density versus voltage characteristic for the quantum dot solar cell reveals a decrease in the series resistance as the device area is reduce from 0.16 cm2 to 0.01 cm2. This is effect is not observed in control devices and is quantum dot related. Furthermore, low temperature measurements of the open circuit voltage for both quantum dot and control devices provide experimental verification of the conditions required to realise an intermediate band gap solar cell.

Quantum-Well Solar Cells

MRS Bulletin ◽  
1993 ◽  
Vol 18 (10) ◽  
pp. 51-55 ◽  
Author(s):  
Keith Barnham ◽  
Jenny Barnes ◽  
Guido Haarpaintner ◽  
Jenny Nelson ◽  
Mark Paxman ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Quantum Well ◽  
Quantum Wells ◽  
Forward Bias ◽  
Flat Band ◽  
Output Current ◽  
Novel Approach ◽  
Modulator Structure ◽  
Conventional Cell

The best present-day single-bandgap solar cells have efficiencies around 20–25%. However, the Carnot efficiency of the earth-sun system is 95%, so there is considerable potential for improvement. The fundamental efficiency limitation in a conventional solar cell results from the tradeoff between a low bandgap which maximizes light absorption and hence output current and a high bandgap which maximizes output voltage. As a result, the maximum theoretical efficiency of a conventional solar cell is around 30% in unconcentrated sunlight at a bandgap close to that of GaAs.The quantum-well solar cell is a novel approach to higher efficiency. In its simplest form, shown in Figure 1, it consists of a multiquantum-well (MQW) system in the undoped region of a p-i-n solar cell. For light with energy greater than the band-gap Eg, the quantum-well cell behaves like a conventional cell. However, light with energy below Eg can be absorbed in the quantum wells. Our studies show that if the material quality is good, the electrons and holes escape from the wells and contribute to a higher output current at a voltage between that of the barrier and well material. In AlGaAs/GaAs test devices, we have obtained efficiency enhancements of a factor of more than two when cells with quantum wells are compared with identical cells without wells.The structure in Figure 1 is, of course, essentially similar to the MQW photodiode or modulator structure that operates in reverse bias, and the quantum-well laser that operates in forward bias beyond flat band.

scholarly journals Highly Mismatched Alloys for Intermediate Band Solar Cells

2005 ◽  
Vol 865 ◽  
Author(s):  
W. Walukiewicz ◽  
K. M. Yu ◽  
J Wu ◽  
J. W. Ager ◽  
W. Shan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Ion Beam ◽  
Detailed Balance ◽  
Solar Cell Performance ◽  
Intermediate Band ◽  
Intermediate Band Solar Cell ◽  
Balance Analysis ◽  
Highly Mismatched Alloys ◽  
Limiting Efficiency

AbstractIt has long been recognized that the introduction of a narrow band of states in a semiconductor band gap could be used to achieve improved power conversion efficiency in semiconductor-based solar cells. The intermediate band would serve as a “stepping stone” for photons of different energy to excite electrons from the valence to the conduction band. An important advantage of this design is that it requires formation of only a single p-n junction, which is a crucial simplification in comparison to multijunction solar cells. A detailed balance analysis predicts a limiting efficiency of more than 50% for an optimized, single intermediate band solar cell. This is higher than the efficiency of an optimized two junction solar cell. Using ion beam implantation and pulsed laser melting we have synthesized Zn1-yMnyOxTe1-x alloys with x<0.03. These highly mismatched alloys have a unique electronic structure with a narrow oxygen-derived intermediate band. The width and the location of the band is described by the Band Anticrossing model and can be varied by controlling the oxygen content. This provides a unique opportunity to optimize the absorption of solar photons for best solar cell performance. We have carried out systematic studies of the effects of the intermediate band on the optical and electrical properties of Zn1-yMnyOxTe1-x alloys. We observe an extension of the photovoltaic response towards lower photon energies, which is a clear indication of optical transitions from the valence to the intermediate band.

scholarly journals Second harmonic generation from metamaterials strongly coupled to intersubband transitions in quantum wells

2014 ◽  
Vol 104 (13) ◽  
pp. 131104 ◽  
Author(s):  
Salvatore Campione ◽  
Alexander Benz ◽  
Michael B. Sinclair ◽  
Filippo Capolino ◽  
Igal Brener
Keyword(s):  
Second Harmonic Generation ◽  
Quantum Wells ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Intersubband Transitions ◽  
Strongly Coupled

scholarly journals The Effect of Noise-Induced Quantum Coherence in the Intermediate Band Solar Cells

2021 ◽  
Author(s):  
Mohsen Daryani ◽  
Ali Rostami ◽  
Gaffar Darvish ◽  
Mohammad Kazem Morravej Farshi
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Output Power ◽  
Quantum Coherence ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Incoherent Light ◽  
Intermediate Band ◽  
Intermediate Band Solar Cells ◽  
Coherence Effect

Abstract It has been shown that quantum coherence induced by incoherent light can increase the efficiency of solar cells. Here we evaluate the effect of such coherence in the intermediate band solar cells. We first examine a six-level quantum IBSC model and demonstrate by simulation that the maximum of output power in a solar cell with quantum structure increases more than 16 percent in the case of coherence existence. We then propose an IBSC model which can absorb continuous spectra of sunlight and show that the quantum coherence can increase the output power of the cell. For instance, calculations indicate that the coherence makes an increase of about 31% in the maximum output power of a cell that the width of the conduction and intermediate bands are 100 and 10 meV, respectively. Also, our calculations show that the quantum coherence effect is still observed in increasing the solar cell power by expanding the width of the conduction band, although the output power is reduced due to increase in the thermalization loss. However, expanding the width of the intermediate band reduces the coherence effect.

scholarly journals A III-nitride nanowire solar cell fabricated using a hybrid coaxial and uniaxial InGaN/GaN multi quantum well nanostructure

RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 20585-20592 ◽  
Author(s):  
Ji-Hyeon Park ◽  
R. Nandi ◽  
Jae-Kwan Sim ◽  
Dae-Young Um ◽  
San Kang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Quantum Well ◽  
Quantum Wells ◽  
Cap Layer ◽  
Multi Quantum Well

Solar cells fabricated with hybrid nanowires comprising InGaN/GaN uniaxial and coaxial multi-quantum wells with an InGaN nano-cap layer.

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