Hua Zhang

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Related publications (92)

Photovoltaic behaviour of lead methylammonium triiodide perovskite solar cells down to 80 K

Michael Graetzel, Shaik Mohammed Zakeeruddin, Hua Zhang, Mingkui Wang, Thomas Moehl

We have tested the photovoltaic metrics of CH3NH3PbI3 perovskite solar cells over a wide temperature range from 80-360 K. Our investigation reveals that the open-circuit voltage reaches a maximum value at about 200 K close to the phase transition from tetr ...

Royal Society of Chemistry2015

Core-shell InGaN/GaN nanowire light emitting diodes analyzed by electron beam induced current microscopy and cathodoluminescence mapping

Hua Zhang, Gwénolé Jean Jacopin

We report on the electron beam induced current (EBIC) microscopy and cathodoluminescence (CL) characterization correlated with compositional analysis of light emitting diodes based on core/shell InGaN/GaN nanowire arrays. The EBIC mapping of cleaved fully ...

Royal Soc Chemistry2015

Characterization and modeling of a ZnO nanowire ultraviolet photodetector with graphene transparent contact

Hua Zhang, Gwénolé Jean Jacopin

We report the demonstration of a ZnO nanowire ultraviolet photodetector with a top transparent electrode made of a few-layered graphene sheet. The nanowires have been synthesized using a low-cost electrodeposition method. The detector is shown to be visibl ...

American Institute of Physics2013

Complex-coupled photonic crystal THz lasers with independent loss and refractive index modulation

Romuald Houdré, Jérôme Faist, Hua Zhang

Compared to near infra-red photonic crystal (PhC) band-edge lasers, achieving vertical emission with quantum cascade (QC) material operating in the THz range needs dedicated engineering because the TM polarized emission of QCLs favors in-plane emitting sch ...

2011

Statistical analysis of subnanometer residual disorder in photonic crystal waveguides: Correlation between slow light properties and structural properties

Romuald Houdré, Nicolas Le Thomas, Hua Zhang, Zhaolu Diao

The authors present a statistical study of residual disorder in nominally identical planar photonic crystal waveguides operating in the slow light regime. The focus is on the role played by the subnanometer scaled residual disorder inherent to state-of-the ...

2011

Refractive Index Gas Sensing in a Hollow Photonic Crystal Cavity

Romuald Houdré, Nicolas Le Thomas, Hua Zhang, Jana Jágerská, Zhaolu Diao

We investigate hollow photonic crystal structures consisting in air-slot photonic crystal nanocavities. The high quality factor similar to 2.6x10(4) of such cavities along with a strong overlap between the resonant mode and the hollow core region allows fo ...

Ieee2011

Development of Terahertz Photonic Crystal Quantum Cascade Lasers and Investigation on IIIV&SOI Photonic Structures at Near-Infrared Wavelength

Hua Zhang

Photonic crystals (PhC) are periodically structured electromagnetic media, in which light within some frequency ranges cannot propagate through the structure. Such frequency ranges are commonly referred as photonic band gaps (PBG). The length scale of the ...

EPFL2010

A NUMERICAL MANIFOLD METHOD FOR PLANE MICROPOLAR ELASTICITY

Jian Zhao, Hua Zhang, Gaofeng Zhao

A numerical manifold method (NMM) for plane micropolar elasticity is proposed in this paper to consider the microstructure influence of materials. First, the basic formulations of plane micropolar elasticity are briefly introduced. Then, the equations of s ...

2010

Design and fabrication technology for high performance electrical pumped terahertz photonic crystal band edge lasers with complete photonic band gap

Romuald Houdré, Jérôme Faist, Hua Zhang

We detail the design and fabrication technology of two-dimensional photonic crystal (PhC) band edge emitting quantum cascade lasers (QCLs) operating at terahertz frequencies (similar to 3.3 THz). The entire QCL active layer has been deeply etched to form a ...

2010

Refractive index sensing with an air-slot photonic crystal nanocavity

Romuald Houdré, Nicolas Le Thomas, Hua Zhang, Jana Jágerská, Zhaolu Diao

We investigate an air-slot photonic crystal cavity for high-precision refractive index sensing. The high quality factor ∼2:6 × 10^4 of the cavity, along with a strong overlap between the resonant mode and the hollow core region, allows us to achieve an exp ...

Optical Society of America2010

Radiation loss of photonic crystal coupled-cavity waveguides

Romuald Houdré, Nicolas Le Thomas, Hua Zhang, Jana Jágerská

We experimentally investigate the out-of-plane radiation losses of photonic crystal coupled-cavity waveguides. We observe a strong variation in the losses along the dispersion curve and show that such variation is closely linked with the specific far-field ...

American Institute of Physics2009

Terahertz photonic crystal quantum cascade lasers

Romuald Houdré, Jérôme Faist, Hua Zhang

We combine photonic crystal and quantum cascade band engineering to create an in-plane laser at terahertz frequency. We demonstrate that such photonic crystal lasers strongly improve the performances of terahertz quantum cascade material in terms of thresh ...

Optical Society of America2007

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