Minority-carrier lifetime in Al<i>x</i>Ga1−<i>x</i>As grown by molecular-beam epitaxy

Ahrenkiel, R. K.; Keyes, B. M.; Shen, Tianze; Chyi, Jen‐Inn; Morkoç̌, H.

doi:10.1063/1.348573

Cited by 18 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Meaning X aluminium mole fraction D diffusivity [10] L diffusion length [10], [14], [15] E effective electric field [5], [6], [8] = ∇xEg S surface recombination velocity [9] E f…”

Section: Parametermentioning

confidence: 99%

Short circuit current enhancement in GaAs/AlGaAs MQW solar cells

Connolly,

Barnham,

Nelson

et al. 2016

Preprint

View full text Add to dashboard Cite

The GaAs/AlxGa 1−x As quantum well solar cell (QWSC) shows promise as a novel approach to higher efficiency solar cells but suffers from a poor short circuit current Jsc. We report on efforts to reduce this problem with the use of compositional grading and back surface mirroring. We present experimental quantum efficiency (QE) data on a range of compositionally graded QWSCs and devices in which the back surface of the cell is coated with a mirror, increasing the optical thickness of the quantum well layer in the long wavelength range. The experimental QE spectra are reproduced by a model which deals with arbitrary compositional profiles and optical cavities formed in the mirrored cells. The model is used to design an optimised QWSC, and projected Jsc values given. Applications including II-VI and tandem solar cells are considered.

show abstract

“…Meaning X aluminium mole fraction D diffusivity [10] L diffusion length [10], [14], [15] E effective electric field [5], [6], [8] = ∇xEg S surface recombination velocity [9] E f…”

Section: Parametermentioning

confidence: 99%

Short circuit current enhancement in GaAs/AlGaAs MQW solar cells

Connolly,

Barnham,

Nelson

et al. 2016

Preprint

View full text Add to dashboard Cite

show abstract

“…Ahrenkiel et al measured electron lifetime of 13.6ns (uncorrected for interface recombinations) in 1.79eV AlGaAs with a hole concentration of 5×10 16 cm −3 . Takahashi et al used 1.87eV AlGaAs as an active junction in a solar cell and obtained good performances.…”

Section: Materials Considerationsmentioning

confidence: 99%

Novel multijunction solar cell design for low cost, high concentration systems

Paquette

Boucherif

Aimez

et al. 2015

Prog. Photovolt: Res. Appl.

View full text Add to dashboard Cite

In the quest to reduce the levelized cost of energy, recent concentrated photovoltaics innovations have striven to increase the solar cell conversion efficiency. Another approach aims at concentrating more light on the solar cell in order to reduce its share of the energy cost. We propose new cell structures that are tailored for high conversion efficiency at solar concentration exceeding 1000 suns, with a minimum amount of heat generated. These designs are composed of multiple junctions (3, 4, and 5) of materials lattice matched to gallium arsenide (GaAs) with bandgaps at or above that of GaAs. Simulations that include thermal effects and electrical resistance effects are used to predict the performances of the proposed designs under high concentrations. A relative cost analysis shows a reduction in electricity cost when using these designs compared with the state of the art triple-junction solar cell. Further cost reduction schemes using these proposed designs are discussed.

show abstract

“…Minority carrier lifetimes in GaAs/Al x Ga 1−x As have been measured for a range of aluminium compositions. The most common methods are time resolved photo-luminescence (TRPL) (Ahrenkiel [41]) and zero-field time-of-flight (ZFTOF) (Zarem [42]) techniques.…”

Section: Minority Carrier Lifetimementioning

confidence: 99%

Modelling and Optimising GaAs/Al(x)Ga(1-x)As Multiple Quantum Well Solar Cells

Connolly

2010

Preprint

View full text Add to dashboard Cite

The quantum well solar cell (QWSC) is a p -i -n solar cell with quantum wells in the intrinsic region. Previous work has shown that QWSCs have a greater open circuit voltage (V oc ) than would be provided by a cell with the quantum well effective bandgap. This suggests that the fundamental efficiency limits of QWSCs are greater than those of single bandgap solar cells.The following work investigates QWSCs in the GaAs/Al x Ga 1−x As materials system. The design and optimisation of a QWSC in this system requires studies of the voltage and current dependencies on the aluminium fraction. QWSCs with different aluminium fractions have been studied and show an increasing V oc with increasing barrier aluminium composition.The QE however decreases with increasing aluminium composition. We develop a model of the QE to test novel QWSC designs with a view to minimising this problem. This work concentrates on two design changes. The first deals with compositionally graded structures in which the bandgap varies with position. This bandgap variation introduces an quasi electric field which can be used to increase minority carrier collection in the low efficiency p and n layers. This technique also increases the light flux reaching the highly efficient depletion regions.The second design change consists of coating the back of the cell with a mirror to exploit the portion of light which is not absorbed on the first pass.A model of the QE of compositionally graded QWSC solar cells with back surface mirrors is developed in order to analyse the effect of these design changes. These changes are implemented separately in a number of QWSC designs and the resulting experimental data compared with the model. An optimised design is then presented. There are those who are overseas -Chris and Olenka, Marc and Malar and the Smiths, Claire and the Granjon Clan. All the Tuckmans and associates in North London apart from Jo in Guatemala, Kerry and Alberta, Karen in the East, (big) Phil, (other) Phil, Hiroe, Bruce who used to be in the West, Paul and Catherine in the centre, Vince in Cambridge, the Marchants (Pete and Jo) and Kul. Then theres Tanveer (I won, I think?),

show abstract

Minority-carrier lifetime in AlxGa1−xAs grown by molecular-beam epitaxy

Cited by 18 publications

References 9 publications

Short circuit current enhancement in GaAs/AlGaAs MQW solar cells

Short circuit current enhancement in GaAs/AlGaAs MQW solar cells

Novel multijunction solar cell design for low cost, high concentration systems

Modelling and Optimising GaAs/Al(x)Ga(1-x)As Multiple Quantum Well Solar Cells

Contact Info

Product

Resources

About