A light-emitting device includes a substrate having a top surface, wherein the top surface includes a first portion and a second portion; a first semiconductor stack including a first upper surface and a first side wall, wherein the first semiconductor stack is on the first portion; a second semiconductor stack including a second upper surface and a second side wall, wherein the second semiconductor stack is on the first upper surface, and wherein the second side wall is devoid of connecting the first side wall; a plurality of first concavo-convex structures on the first portion; and a plurality of second concavo-convex structures on the second portion; wherein the first side wall and the second portion of the top surface form an acute angle between thereof; and wherein the second concavo-convex structures have smaller size than that of the first concavo-convex structures.

A micro device transferring method and a micro device transferring apparatus are provided. The micro device transferring method exemplarily includes: providing a carrier substrate including a transparent base, a light radiation activated adhesiveness-loss layer located on a first surface of the transparent base and multiple micro devices arranged in an array on the light radiation activated adhesiveness-loss layer; locally irradiating the light radiation activated adhesiveness-loss layer from a second surface of the transparent base to reduce adhesiveness of multiple target areas of the light radiation activated adhesiveness-loss layer to the micro devices respectively located in the multiple target areas, the multiple target areas being areas corresponding to the micro devices to be transferred; picking up the micro devices in the multiple target areas; and aligning the picked up micro devices with corresponding locations of a receiving substrate, and releasing them onto the receiving substrate.

A light emitting diode (LED) including an epitaxial stacked layer, first and second reflective layers which are disposed at two sides of the epitaxial stacked layer, a current conducting layer and first and second electrodes and a manufacturing thereof are provided. The epitaxial stacked layer includes a first-type and a second-type semiconductor layers and an active layer. A main light emitting surface with a light transmittance >0% and 10% is formed on one of the two reflective layers. The current conducting layer contacts the second-type semiconductor layer. The first electrode is electrically connected to the first-type semiconductor layer. The second electrode is electrically connected to the second-type semiconductor layer via the current conducting layer. A contact scope of the current conducting layer and the second-type semiconductor layer is served as a light-emitting scope overlapping the two layers, but not overlapping the two electrodes.

An optoelectronic device with a multi-layer contact is described. The optoelectronic device can include an n-type semiconductor layer having a surface. A mesa can be located over a first portion of the surface of the n-type semiconductor layer and have a mesa boundary, which has a shape including a plurality of interconnected fingers. The n-type semiconductor layer can have a shape at least partially defined by the mesa boundary. A first n-type contact layer can be located adjacent to another portion of the n-type semiconductor contact layer, where the first n-type contact layer forms an ohmic contact with the n-type semiconductor layer. A second contact layer can be located over a second portion of the n-type semiconductor contact layer, where the second contact layer is formed of a reflective material.

An embodiment provides a light emitting element comprising: a first conductive semiconductor layer including a first layer and a second layer; an active layer on the first conductive semiconductor layer; a second conductive semiconductor layer on the active layer; and a first electrode and a second electrode arranged on the first conductive semiconductor layer and the second conductive semiconductor layer, respectively, wherein the first layer includes a plurality of first grooves, and a growth prevention layer is arranged on the bottom surface and side surfaces of each of the first grooves.

A substrate has a first surface with at least one division line formed thereon and a second surface opposite the first surface. The substrate is processed by applying a pulsed laser beam from the side of the first surface. The substrate is transparent to the pulsed laser beam. The pulsed laser beam is applied at least in a plurality of positions along the at least one division line, a focal point of the pulsed laser beam located at a distance from the first surface in the direction from the first surface towards the second surface, so as to form a plurality of modified regions inside the substrate. Each modified region is entirely within the bulk of the substrate, without any openings open to the first surface or the second surface. Substrate material is removed along the at least one division line where the modified regions are present.

A gallium nitride (GaN) based light emitting diode (LED), wherein light is extracted through a nitrogen face (N-face) of the LED and a surface of the N-face is roughened into one or more hexagonal shaped cones. The roughened surface reduces light reflections occurring repeatedly inside the LED, and thus extracts more light out of the LED. The surface of the N-face is roughened by an anisotropic etching, which may comprise a dry etching or a photo-enhanced chemical (PEC) etching.

Semiconductor optoelectronic devices having a dilute nitride active layer are disclosed. In particular, the semiconductor devices have a dilute nitride active layer with a bandgap within a range from 0.7 eV and 1 eV. Photodetectors comprising a dilute nitride active layer have a responsivity of greater than 0.6 A/W at a wavelength of 1.3 m.

There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient is approximately expressed by equation (1) in a wavelength range of at least 1 m or more and 3.3 m or less: =n K.sup.a (1) (wherein, (m) is a wavelength, (cm.sup.1) is absorption coefficient of the nitride crystal substrate at 27 C., n (cm.sup.3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.510.sup.19K6.010.sup.19, a=3).

Micro light-emitting diode display fabrication processes and assembly apparatuses are described. In an example, a micro light emitting diode pixel structure includes a backplane including a glass substrate having an insulating layer disposed thereon, and a pixel thin film transistor circuit disposed in and on the insulating layer, the pixel thin film transistor circuit including a gate electrode and a channel. The micro light emitting diode pixel structure also includes a front plane including a metal pad coupled to the pixel thin film transistor circuit of the backplane, a micro light emitting diode device bonded to the metal pad, a spacer adjacent sidewalls of the micro light emitting diode, the spacer including a high refractive index material, and an insulating layer surrounding the spacer.