Effects of CdS buffer layers on photoluminescence properties of Cu(In,Ga)Se2 solar cells

Shirakata, Sho; Katsuhiko, Ohkubo; Ishii, Yasuyuki; Nakada, Tokio

doi:10.1016/j.solmat.2008.11.043

Cited by 78 publications

(61 citation statements)

References 11 publications

(24 reference statements)

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“…26,31 In the CIGS layer on SLG, the PL peak of 0.97 eV stems from the optical transition between the shallow acceptor level of 50 meV formed by Cu vacancies (V Cu ) and the donor level of 80 meV created by the Se vacancy (V Se ). 29 In CIGS on BS, a new defect level emerges. It is plausible to assign this as an optical transition from antisite In Cu as a donor level of descending order to V Cu .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se₂ Measured by Optical Pump-Terahertz Probe Spectroscopy

Lee

Cho

et al. 2015

J. Phys. Chem. C

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To investigate the origin of the Na effect on photovoltaic (PV) devices, Cu(In,Ga)Se 2 (CIGS) and CdS/ CIGS layers were grown on borosilicate (BS) and soda-lime glass (SLG), respectively. The defect states and nonequilibrium carrier dynamics of the samples were measured using photoluminescence (PL) and optical pump-THz probe (OPTP) spectroscopy. From the PL results, we discovered that different shallow donor−acceptor levels were formed in the CIGS layer grown on BS and SLG, respectively. In the OPTP results, relaxation times of photocarriers excited from the CdS/CIGS layer were clearly distinguishable, and are explained by the formation of different defect states depending on substrates. In BS, deep defect level 'DX states' were formed in the E g near the p−n junction, which induce trapping photocarriers, resulting in shortening relaxation time. In SLG, there was no "DX state", which clearly demonstrates the positive effect of Na atoms at the p−n junction on performance of PV devices.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se₂ Measured by Optical Pump-Terahertz Probe Spectroscopy

Lee

Cho

et al. 2015

J. Phys. Chem. C

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“…For that purpose, we start by discussing the dependence on excitation power and temperature of PL for both types of materials. Regarding the effect on the PL of the increase of excitation power, the peak energy evidences a blueshift that in some cases is just of a few meV/decade (but it should also be noticed that in some cases, no dependence was reported) [12,13,36,53] and, in other cases, considerably higher values were reported [10][11][12][13][30][31][32][33][34][35]37]. The case with a blueshift with few meV/decade was usually observed in Cu-rich films and the estimated values for the m parameter [see Eq .…”

Section: Recombination Modelsmentioning

confidence: 89%

“…The mechanisms for radiative transitions depend mainly on the doping and compensation levels, which in these materials are mostly due to intrinsic defects. Different models are considered in the literature [10][11][12][13][14]23,[30][31][32][33][34][35][36][37], namely, excitonic recombination, free-to-bound transition, donoracceptor pair (DAP) recombination, quasi-DAP (QDAP) recombination, and radiative channels involving fluctuating potentials. Concerning the latter, band-gap and electrostatic fluctuations resulting from structural and electronic inhomogeneities have an important influence on the recombination mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Teixeira

Sousa

et al. 2014

Phys. Rev. B

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The theoretical models of radiative recombinations in both CuIn 1−x Ga x Se 2 chalcopyrite and Cu 2 ZnSnS 4 kesterite, and related compounds, were revised. For heavily doped materials, electrons are free or bound to large donor agglomerates which hinders the involvement of single donors in the radiative recombination channels. In this work, we investigated the temperature and excitation power dependencies of the photoluminescence of Cu 2 ZnSnS 4 -based solar cells in which the absorber layer was grown through sulphurization of multiperiod structures of precursor layers. For both samples the luminescence is dominated by an asymmetric band with peak energy at ∼1.22 eV, which is influenced by fluctuating potentials in both conduction and valence bands. A value of ∼60 meV was estimated for the root-mean-square depth of the tails in the conduction band. The radiative transitions involve the recombination of electrons captured by localized states in tails of the conduction band with holes localized in neighboring acceptors that follow the fluctuations in the valence band. The same acceptor level with an ionization energy of ∼280 meV was identified in both absorber layers. The influence of fluctuating potentials in the electrical performance of the solar cells was discussed.

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“…From then chemical bath deposition (CBD) has been used for decades to deposit thin films of various semiconductors (Hodes, 2003 (Mendoza-Perez et al, 2009;Ochoa-Landın et al, 2009;Lee, 2005;Castillo-Alvarado et al, 2010;Rose et al, 1999;Guillemoles et al, 2000;Hariskos et al, 2005;Kylner, 1999;Shirakata et al, 2009;Ennaoui et al, 2001). It takes advantage of the use of a reaction from a solution were different precursors can be dissolved easily.…”

Section: Chemical Bath Deposition (Cbd)mentioning

confidence: 99%

Nanocomposites for Photovoltaic Energy Conversion

Zeng¹,

Gan²

2011

Advances in Composite Materials for Medicine and Nanotechnology

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Induction Composite materialsA composite is a multiphase solid material. It is incorporated by two or more individual materials through physical or chemical methods. The performance of different materials to complement each other will produce synergistic effects (Ivanov et al., 2008;Lu et al., 2010). The overall property of composite materials is better than that of each original material to meet different requirements. These properties include mechanical, electrical, thermal, optical, electrochemical, catalytic behaviors etc. For example (Lu et al., 2010), investigating the synergistic effect of carbon nano-fiber (CNF) and carbon nano-paper on the shape recovery of shape memory polymer (SMP) composite shows that the combination of CNF and carbon nano-paper can improve the thermal and electrical conductivities of the SMP composite, which are much better than each of the components. The individual materials in a composite are referred to as two constituent materials. The two constituent materials are matrix and reinforcement. The matrix material is a frame to support the reinforcement material. So the reinforcement material can keep its relative position. The reinforcement is a functional material which can enhance the matrix properties. Composite metal matrix (substrates) includes aluminum, copper, titanium, magnesium and its alloys and nonmetallic matrix includes synthesized resin, rubber, ceramics, graphite and carbon and so on. Reinforcement mainly includes glass fiber, carbon fiber, boron fiber , aramid fiber, silicon carbide fiber , asbestos fiber, whisker, metal wire and fine grain etc. In order to make use of synergistic effect to improve composite properties, optimum combination of matrix and reinforcement should be chosen. Nanocomposites and their propertiesA nanocomposite is a special composite where one of the phases has one, two or three dimensions less than 100 nanometers (nm, 10 -9 m). A nanocomposite also includes the material where the structures between the different phases that make up the material are in nano-scale (Beecroft & Ober, 1997). In the broadest sense, nanocomposites can also include porous media, colloids, gels and polymers, because in these materials the particles or structures are in nano scale. One nanometer is equivalent to the length to tightly line up www.intechopen.com Advances in Composite Materials for Medicine and Nanotechnology 212 10~100 atoms. Nano-materials include nano-powders, nano-fibers, nano-particles and nanothin films. Their structures are between atom (molecular) size and macro size. Materials in nano-scale have special effects such as quantum size effect, surface effect, small-size effect and macroscopic quantum tunneling effect etc. Quantum size effectQuantum size effect is one of the fundamental physical properties of nano-particles. When the particle size decreases to a nano-scale, the electronic energy levels of the particle atom become discrete and the energy gap becomes wider. This phenomenon is called quantum size effect. This effect does not come into ...

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Effects of CdS buffer layers on photoluminescence properties of Cu(In,Ga)Se2 solar cells

Cited by 78 publications

References 11 publications

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se₂ Measured by Optical Pump-Terahertz Probe Spectroscopy

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se₂ Measured by Optical Pump-Terahertz Probe Spectroscopy

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Nanocomposites for Photovoltaic Energy Conversion

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Effects of CdS buffer layers on photoluminescence properties of Cu(In,Ga)Se2 solar cells

Cited by 78 publications

References 11 publications

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se2 Measured by Optical Pump-Terahertz Probe Spectroscopy

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se2 Measured by Optical Pump-Terahertz Probe Spectroscopy

Radiative transitions in highly doped and compensated chalcopyrites and kesterites: The case ofCu2ZnSnS4

Nanocomposites for Photovoltaic Energy Conversion

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Product

Resources

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Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se₂ Measured by Optical Pump-Terahertz Probe Spectroscopy

Na-Dependent Ultrafast Carrier Dynamics of CdS/Cu(In,Ga)Se₂ Measured by Optical Pump-Terahertz Probe Spectroscopy