Concept

Sapphire

Related publications (112)

Self-limitation of AlGaN/GaN quantum well energy by built-in polarization field

Wurtzite AlGaN/GaN quantum well (QW) structures were grown by molecular beam epitaxy on c-plane sapphire substrates and the QW transition energies were measured by low temperature photoluminescence. Both the well widths and the Al mole fraction in the AlxG ...

1999

Built-in electric-field effects in wurtzite AlGaN/GaN quantum wells

Nicolas Grandjean

AlGaN/GaN quantum well (QW) structures are grown on c-plane sapphire substrates by molecular beam epitaxy. Control at the monolayer scale of the well thickness is achieved and sharp QW interfaces are demonstrated by the low photoluminescence linewidth. The ...

1999

Photoreflectance investigations of the bowing parameter in AlGaN alloys lattice-matched to GaN

Nicolas Grandjean

Room temperature photoreflectance investigations have been performed on a series of AlGaN layers grown both by metalorganic vapor phase epitaxy and molecular beam epitaxy on c-plane sapphire substrates. The aluminum composition was ranging between 0% and 2 ...

1999

GaN evaporation in molecular-beam epitaxy environment

Nicolas Grandjean

GaN(0001) thick layers were grown on c-plane sapphire substrates by molecular-beam epitaxy using NH3. The evaporation of such GaN layers in vacuum was studied as a function of substrate temperature. In situ laser reflectivity was used to quantitatively mea ...

1999

Molecular-beam epitaxy of gallium nitride on (0001) sapphire substrates using ammonia

Nicolas Grandjean

Ammonia is used for growing undoped GaN layers by gas source molecular-beam epitaxy on c-plane sapphire substrates. The growth mode is layer by layer as shown by the observation of reflection high-energy electron diffraction intensity oscillations. The str ...

1998

Quantum confined Stark effect due to built-in internal polarization fields in (Al,Ga)N/GaN quantum wells

Nicolas Grandjean

(Al,Ga)N/GaN quantum wells have been studied by temperature-dependent luminescence and reflectivity. The samples were grown by molecular beam epitaxy on (0001) sapphire substrates, and well widths were varied from 3 to 15 monolayers (ML's) with a 2-ML incr ...

1998

Ultraviolet GaN light-emitting diodes grown by molecular beam epitaxy using NH3

Nicolas Grandjean

Si- and Mg-doped GaN layers were grown on c-plane sapphire substrates by molecular beam epitaxy with NH3 as the nitrogen precursor. Their optical and electrical properties were investigated by photoluminescence experiments and Hall measurements, respective ...

1998

Si and Mg doped GaN layers grown by gas source molecular beam epitaxy using ammonia

Nicolas Grandjean

The growth of GaN layers was carried out on c-plane sapphire substrates by molecular beam epitaxy (MBE) using NH3. Undoped GaN layers were grown at 830 degrees C with growth rates larger than 1 mu m/h. Optical properties are characteristics of high quality ...

Materials Research Society1998

Real time control of InxGa1-xN molecular beam epitaxy growth

Nicolas Grandjean

The growth of GaN and InxGa1-xN on c-plane sapphire substrates was carried out by molecular beam epitaxy using NH3. bl situ reflection high-energy electron diffraction (RHEED) was used to monitor the growth process. Oscillations of the specular beam intens ...

1998

Violet InGaN/GaN light emitting diodes grown by molecular beam epitaxy using NH3

Nicolas Grandjean

GaN and InGaN alloys were grown on c-plane sapphire substrates by molecular beam epitaxy using NH3. This allows realizing light emitting diodes (LEDs) based on InGaN/GaN single heterostructures. The forward voltage is 3.6 V at 20 mA. The room temperature e ...

1998

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