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Wurtzite structure semiconductors (Nitrides, ZnO)

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Basal stacking faults stopped in the layers of GaN (11-22)

Growth of GaN semipolar (11-22) by the ELO

(a) Schematic diagram of the growth. (b) Weak beam TEM image in cross section g = 0002 : evidence of a clear boundary where the linear defects are stopped. (c) Cross-sectional TEM weak beam image at the coalescence zone obtained with g = 10-10 : Identification of stacking faults (Appl. 98, 121916 (2011))

Degradation of semiconductor nitrides by rare earths ion implantation

GaN after Eu ion implantation (300 keV, fluence : 3 x 10 15 Eu/cm2)

Cross section InN following ion implantation (5 x 10 12 Eu/cm2, along the [11-20] zone axis)

(a) General view of the implanted region. ( b) High resolution image close to the surface. (c) High resolution image at the middle of the implanted area (J. Phys. D : Appl Phys 44 (2011) 295402).

Our data for AlN, GaN, InN, Si (open triangles : Jpn J. Appl. Phys. 52, 11NH02(2013)) added in the graph published by Williams for the amorphization during ion implantation (Mat. Sci. Eng. A253, 8 (1998), an Si implementation study for 100 kV).

Structural units for grain boundaries in the wurtzite structure (ZnO)

The atomic structure of the Σ31 grain boundary in ZnO

The grain boundary dislocations are a = 1/3 [11-20], two per period with their Burgers vector parallel. b) corresponding simulated image : a Burgers circuit was is drawn around one period and next when reported in the perfect crystal, it clearly shows the two "a" dislocations. c) Three periods of the same boundary in high resolution microscopy observed along the [0001] zone axis. This configuration allows to uniquely identify all the elements of the grain boundary : the angle of rotation around the [0001] axis, the plan and the period of this Σ31grain boundary are ( 32.2 ° ) 1/3 [-2 7- 5 0] (-4,1,30) λ .

Indium distribution in the quantum wells and emission efficiency in light emitting diodes

InGaN/GaN quantum wells

Three quantum well InGaN/GaN grown by organometallic vapor phase epitaxy. Changes in contrast due to local strain are visible in the wells.

Strain fluctuation which characterize MVPE InGaN quantum wells

Fluctuations in the local deformation in quantum wells, correlated with the In composition. It is one of the assumptions which are set forward to explain the high quantum efficiency of LED -based quantum well InGaN/GaN