From atomic structure to photovoltaic properties in CdTe solar cells

Li, Chen; Poplawsky, Jonathan D.; Wu, Yelong; Lupini, Andrew R.; Mouti, Anas; Leonard, Donovan N.; Paudel, Naba R.; Jones, K. M.; Yin, Wan‐Jian; Al‐Jassim, Mowafak; Yan, Yanfa; Pennycook, Stephen J.

doi:10.1016/j.ultramic.2013.06.010

Cited by 83 publications

(54 citation statements)

References 67 publications

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“…However, the high-resolution characterization techniques used to obtain these results are destructive, expensive, and time consuming. For example, transmission electron microscopy (TEM) (Li et al, 2013) ) is effective at revealing two-dimensional (2-D) microstructures with atomic resolution, but cannot provide three-dimensional (3-D) information that determines material properties and defect evolution. Moreover, atomic probe tomography (Kelley & Miller, 2007) (Miller & Forbes, 2009) provides rich 3-D compositional information, but is unable to resolve lattice and defect structure with atomic resolution.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of CdTe / CdS Heteroepitaxy - Effect of Substrate Orientation

Chavez¹,

Zhou²,

Almeida³

et al. 2016

JMSR

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Molecular dynamics simulations were used to catalogue atomic scale structures of CdTe films grown on eight wurtzite (wz) and zinc-blende (zb) CdS surfaces. Polytypism, grain boundaries, dislocations and other film defects were detected. Dislocation lines were distributed in three distinct ways. For the growths on the wz {0001} and zb {111} surfaces, dislocations were found throughout the epilayers and formed a network at the interface. The dislocations within the films grown on the wz {1 100}, wz {112 0}, zb {1 10}, zb {010}, and zb { 1 } surfaces formed an interface network and also threaded from the interface towards the film's surface. In contrast, the growth on the zb {112 } surface only had dislocations localized to the interface. This film exhibited a different orientation from the substrate to reduce the lattice mismatch strain energies, and therefore, its misfit dislocation density. Our study indicates that the substrate orientation could be utilized to modify the morphology of dislocation networks in lattice mismatched multi-layered systems.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of CdTe / CdS Heteroepitaxy - Effect of Substrate Orientation

Chavez¹,

Zhou²,

Almeida³

et al. 2016

JMSR

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“…CdTe is a unique among II-IV group of binary semiconducting compounds, as it has both p-and n-type conduction [2]. This permits the fabrication of solar cells in both homo-and heterojunction configuration [3][4][5][6]. Its band gap about 1.5eV, just in the middle of the solar spectrum, and possess high absorption coefficient (α) (>10 4 cm -1 ) for the visible solar spectrum make CdTe very good candidate material for photovoltaic conversion [7].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Dopant and Substrate Temperature on the Current-Volltage Characteristics for CdTe/P-GaAs Heterojunction

Shaikley¹,

Alias²,

Alnajjar³

et al. 2014

IJIRSET

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Thin films of undoped and doped CdTe with thickness around 500±10nm were deposited by thermal evaporation technique onto (100) p-GaAs wafer. The effect of both Al and Sb dopant percentages (0.5, 1.5 and 2.5) and substrate temperatures (RT and 423K) on the optoelectronic properties of CdTe/p-GaAs heterojunction was studied. I-V characteristics under illumination for the prepared CdTe/p-GaAs heterojunctions showed a good significant photovoltaic effect. The value of short circuit current (I sc ) for CdTe/p-GaAs heterojunction doped with Sb was higher than that doped with Al. The effect of Al doping on the value of the open-circuit voltage (V oc ) was more than Sb doped. The outcomes of all these measurements for various (Al and Sb)doping of thin CdTe deposited on GaAs were indicated that 2.5%Sb-doped CdTe/p-GaAs heterojunctions deposited at RT and 423K posses a good response to illumination which make it a candidate for heterojunction device used as basic for fabricating photo sensors.

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“…It is known that full dislocations such as edge or screw dislocations can dissociate into Shockley partial dislocations, which have higher mobility than full dislocations. However, direct observation of the Shockley partial dislocation movements at the atomic level has not been achieved before.In this research, we use 5 th order aberration-corrected scanning transmission electron microscopes (STEM) with sub-Å resolution to identify the atomic structure of different types of dislocations in CdTe solar cell materials [2]. The STEM Z-contrast image in Fig.…”

mentioning

confidence: 99%

“…In this research, we use 5 th order aberration-corrected scanning transmission electron microscopes (STEM) with sub-Å resolution to identify the atomic structure of different types of dislocations in CdTe solar cell materials [2]. The STEM Z-contrast image in Fig.…”

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Column-by-Column Imaging of Dislocation Slip Processes in CdTe

Lupini

et al. 2014

Microsc Microanal

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The migration of dislocations affects many material properties including deformation, plasticity and electronic properties. In order to understand the mechanism of the motion of dislocations, both experimental and theoretical studies have been performed [1]. It is known that full dislocations such as edge or screw dislocations can dissociate into Shockley partial dislocations, which have higher mobility than full dislocations. However, direct observation of the Shockley partial dislocation movements at the atomic level has not been achieved before.In this research, we use 5 th order aberration-corrected scanning transmission electron microscopes (STEM) with sub-Å resolution to identify the atomic structure of different types of dislocations in CdTe solar cell materials [2]. The STEM Z-contrast image in Fig. 1 (a) shows a pair of 30° Shockley partial dislocations at the two ends of an intrinsic stacking fault, which are likely to have dissociated from a screw dislocation [2]. Unpaired Cd and Te columns have been resolved in each core. Based on the STEM images, an atomic model has been built and relaxed with density-functional theory (DFT), and the structure along the dislocation line can be understood [3]. Different from the cases of Si and diamond [1], no dimer has been found along the dislocation core ( Fig. 1(c). Kinks along the dislocations can also be located in three dimensions using through-focus imaging. Similar unpaired Cd or Te columns have been observed at both 30° and 90° Shockley partial dislocations associated with extrinsic stacking faults. Fig. 2 (a) shows two unpaired Cd columns in a 90° Shockley partial dislocation associated with an extrinsic stacking fault. However, instead of unpaired columns, CdTe-TeCd or TeCd-CdTe bonding has been observed at 90° Shockley partial dislocations associated with an intrinsic stacking fault. Moreover, we have been able to directly watch the dislocation movement by stimulating the dislocation with the electron beam, meanwhile the low beam energy (60 KV) and low-current mode can protect the samples from being damaged. Several movies will be shown in the presentation. One movie shows the 90° Shockley partial dislocation of Fig. 2(a) gliding back and forth along the stacking fault. Three continuous frames were cut from the movie, demonstrating the glide mechanism column by column (Fig. 2 (b-d)). The Cd 0 column in fig. 2(b) was unpaired, while Cd 1 -Te 1 and Cd 2 -Te 2 form two dumbbells. But in fig. 2(c), the bonding between Cd 2 and Te 2 has been broken. Te 2 reformed a dumbbell with Cd 0 , leaving Cd 2 as a new unpaired column. In fig. 3(d), Te 2 broke the bonding with Cd 0 , and re-bonded with Cd 2 . A similar movement happened simultaneously on another unpaired Cd column. This movie clearly demonstrates the glide mechanism is bond-breaking and bond-exchange. However, instead of the unpaired columns, the columns which actually move are the ones nearby. Shockley partial dislocations with unpaired columns all show a similar glide mechanism. Nevertheless, the 90° S...

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From atomic structure to photovoltaic properties in CdTe solar cells

Cited by 83 publications

References 67 publications

Molecular Dynamics Simulations of CdTe / CdS Heteroepitaxy - Effect of Substrate Orientation

Molecular Dynamics Simulations of CdTe / CdS Heteroepitaxy - Effect of Substrate Orientation

The Influence of Dopant and Substrate Temperature on the Current-Volltage Characteristics for CdTe/P-GaAs Heterojunction

Column-by-Column Imaging of Dislocation Slip Processes in CdTe

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