Strain relaxation in ultrathin films: A modified theory of misfit-dislocation energetics

Payne, A. P.; Lairson, B. M.; Clemens, Bruce M.

doi:10.1103/physrevb.47.13730

Cited by 28 publications

(15 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, we use our high‐fidelity BOP approach to derive the misfit strain energy density and dislocation line energy as functions of island dimensions and lattice mismatch assuming that these islands are independent. These functions are then used to accurately calculate the dislocation density in nano‐patterned multilayers according to classic misfit dislocation theory .…”

Section: Theoretical Prediction Of Defect‐free Cdte/cds Solar Cellsmentioning

confidence: 99%

A prediction of dislocation‐free CdTe/CdS photovoltaic multilayers via nano‐patterning and composition grading

Zhou

Ward

Doty

et al. 2015

Progress in Photovoltaics

View full text Add to dashboard Cite

Defects in multilayered films have long been a performance‐limiting problem for the semiconductor industry. For instance, CdTe/CdS solar cell efficiencies have had significant improvement in the past 15years or more without addressing the problem of high misfit dislocation densities. Overcoming this stagnation requires a fundamental understanding of interfacial defect formation. Herein, we demonstrate a new first principles‐based CdTe bond‐order approach that enables efficient molecular dynamics to approach the fidelity of density functional theory. Stringent quantum‐mechanical verification and experimental validation tests reveal that our new approach provides an accurate prediction of defects that earlier methods cannot. Using this new capability, we show that misfit dislocations in CdTe/CdS multilayers can be significantly reduced via nano‐patterning and composition grading and more importantly, dislocation‐free multilayers naturally arise when the pattern dimension is reduced below 90nm. Our predictive methods are generally applicable to other materials, highlighting a rational approach towards low‐defect semiconductor films. Copyright © 2015 John Wiley & Sons, Ltd.

show abstract

Section: Theoretical Prediction Of Defect‐free Cdte/cds Solar Cellsmentioning

confidence: 99%

A prediction of dislocation‐free CdTe/CdS photovoltaic multilayers via nano‐patterning and composition grading

Zhou

Ward

Doty

et al. 2015

Progress in Photovoltaics

View full text Add to dashboard Cite

show abstract

“…Moreover, as the relaxation increases with the wetting layer thickness, the dislocation density near the interface between the NR and the wetting layer increases (Figs 5e and 5h), which can be due to a complete strain relaxation. 49 However, this density decreases in (Figs 5f and 5i) and above the interface (Figs 5g and 5j). Remarkably, Figs 5f and 5i indicate a rapid reduction in the dislocation density in the interface (see the area circled with yellow in Fig.…”

Section: Growth Mechanismmentioning

confidence: 99%

Homogeneous vertical ZnO nanorod arrays with high conductivity on an in situ Gd nanolayer

et al. 2015

View full text Add to dashboard Cite

CitationFlemban TH, Singaravelu V, Sasikala Devi AA, Roqan IS (2015 We demonstrate a novel, one-step, catalyst-free method for the production of size-controlled vertical highly conductive ZnO NR arrays with highly desirable characteristics by pulsed laser deposition using a Gd-doped ZnO target. Our study shows that an in situ transparent and conductive Gd nanolayer (with a uniform thickness of ~1 nm) at the interface between a latticematched (11-20) a-sapphire substrate and ZnO is formed during the deposition. This nanolayer significantly induces relaxation mechanism that controls the dislocation distribution along the growth direction; which consequently improves the formation of homogeneous vertically aligned ZnO NRs. We demonstrate that both the lattice orientation of the substrate and the Gd characteristics are important in enhancing the NR synthesis, and we report precise control of the NR density by changing the oxygen partial pressure. We show that these NRs possess high optical and electrical quality, with a mobility of 177 cm 2 (V.s), which is comparable to the best-reported mobility of ZnO NRs. Therefore, this new and simple method has significant potential for improving the performance of materials used in a wide range of electronic and optoelectronic applications.

show abstract

“…A rather large number of experimental and theoretical studies have been devoted to the transition from a coherent interface to an incoherent one, 1,2,3 driven by the elastic energy stored in the layer. In the case of nanometric films, the mechanisms at work still raise fundamental questions 4 since the film thickness is comparable to the dislocation core radius. Many fewer studies 5 focus on the chemical gradients that may exist close to interfaces.…”

Section: Introductionmentioning

confidence: 99%

Interfacial structure in (111) Au:Ni multilayers investigated by anomalous x-ray diffraction

et al. 2001

View full text Add to dashboard Cite

We have investigated the structure of buried interfaces in ͑111͒ Au:Ni multilayers. Conventional x-ray diffraction at constant energy as well as anomalous x-ray scattering across the Ni absorption K edge have been used. Whereas the fitting of the spectra at a single energy leads to two different possible interfacial structures, the anomalous diffracted intensity variation unambiguously favors a model with an interfacial concentration gradient at one interface. The multilayer presents an intermixed region extending on six atomic planes around the Ni/Au interface, whereas the Au/Ni interface is chemically abrupt. This structure can explain the unusual stress-strain relation previously reported on this system.

show abstract

Strain relaxation in ultrathin films: A modified theory of misfit-dislocation energetics

Cited by 28 publications

References 16 publications

A prediction of dislocation‐free CdTe/CdS photovoltaic multilayers via nano‐patterning and composition grading

A prediction of dislocation‐free CdTe/CdS photovoltaic multilayers via nano‐patterning and composition grading

Homogeneous vertical ZnO nanorod arrays with high conductivity on an in situ Gd nanolayer

Interfacial structure in (111) Au:Ni multilayers investigated by anomalous x-ray diffraction

Contact Info

Product

Resources

About