Abstract: A flow splitting device for gas reverse circulation drilling, including: an upper joint for connecting with a double-wall drill pipe; an inner tube which is arranged in the upper joint and defines a first passageway in communication with an inner chamber of the double-wall drill pipe, a second passageway in communication with an annular space in the double-wall drill pipe formed between the inner tube and the upper joint; a lower joint, having an upper end fixedly connected with the upper joint and a lower end for connecting with a drill tool; and a flow guiding member provided between the upper joint and the lower joint. A flexible sealing mechanism is provided outside the upper joint. The flexible sealing mechanism extends radially outward relative to the upper joint and the lower joint to form a sealing contact with a wellbore wall.

Abstract: A follow-hold switch circuit comprising: a follower; a sampling sub-circuit for voltage sampling; a bootstrap-control sub-circuit, which provides a bootstrap voltage to the sampling sub-circuit when the circuit is in a following state; a sampling-switch-control sub-circuit, which provides a common-mode voltage to a bootstrap capacitor in the bootstrap-control sub-circuit when the circuit is in a holding state; the follower is connected to an output of the sampling sub-circuit; the sampling sub-circuit is connected to the bootstrap-control sub-circuit and the sampling-switch-control sub-circuit respectively through a sampling switch; the present disclosure can effectively improve the linearity of sampling switches.

Abstract: A nitride-based semiconductor device includes a patterned substrate having an etched surface that is formed with a plurality of protrusions, an aluminum nitride (AlN)-based film disposed on the etched surface, and a nitride-based semiconductor stacked structure disposed on the aluminum nitride-based film. Each of the protrusions has a side face. The AlN-based film includes a plurality of crystal defects formed on the side face of each protrusion. Each of the crystal defects has a width of smaller than 20 nm and/or the number of the crystal defects that are formed on the side face of each protrusion and that have a width of greater than 10 nm is less than 10. A method for preparing the semiconductor device is also disclosed.

Abstract: A nitride-based semiconductor device includes a patterned substrate having an etched surface that is formed with a plurality of protrusions, an aluminum nitride (AlN)-based film disposed on the etched surface, and a nitride-based semiconductor stacked structure disposed on the aluminum nitride-based film. Each of the protrusions has a side face. The AlN-based film includes a plurality of crystal defects formed on the side face of each protrusion. Each of the crystal defects has a width of smaller than 20 nm and/or the number of the crystal defects that are formed on the side face of each protrusion and that have a width of greater than 10 nm is less than 10. A method for preparing the semiconductor device is also disclosed.

Abstract: A light-emitting diode (LED) chip includes from bottom to up: a conductive substrate, a p-type nitride layer, an active layer, an n-type recovery layer, an n-type nitride layer and an n electrode, wherein, the n-type nitride layer has a nitride polarity crystal and a gallium polarity crystal, and the surfaces of the nitride polarity and the gallium polarity regions appear different in height, the n-type recovery layer surface approximate to the n-type nitride layer has consistent mixed polarity with the n-type nitride layer, and the surface far from the n-type nitride layer is a connected gallium polarity surface.

Abstract: A light-emitting diode includes a conductive mask layer planted over a substrate surface. An epitaxial laminated layer is formed over the conductive mask layer via epitaxial growth; and a current channel is formed over the epitaxial laminated layer; during injection, current is firstly conducted to the conductive mask layer through the current channel, and then to the epitaxial laminated layer after horizontal spreading over the conductive mask layer, which effectively improves current spreading uniformity and reduces working voltage of device. Meanwhile, the conductive mask layer reflects light to further improve extraction efficiency and light-emitting luminance.

Abstract: A light-emitting diode (LED) epitaxial structure includes, from bottom to up, a substrate, a first conductive type semiconductor layer, a super lattice, a multi-quantum well layer with V pits, a hole injection layer and a second conductive type semiconductor layer. The hole injection layer appears in the shape of dual hexagonal pyramid, which fills up the V pits and embeds in the second conductive type semiconductor layer. Various embodiments of the present disclosures can effectively reduce point defect density and dislocation density of semiconductor material and effectively enlarge hole injection area and improves hole injection efficiency.

Abstract: A light-emitting diode includes a conductive mask layer planted over a substrate surface. An epitaxial laminated layer is formed over the conductive mask layer via epitaxial growth; and a current channel is formed over the epitaxial laminated layer; during injection, current is firstly conducted to the conductive mask layer through the current channel, and then to the epitaxial laminated layer after horizontal spreading over the conductive mask layer, which effectively improves current spreading uniformity and reduces working voltage of device. Meanwhile, the conductive mask layer reflects light to further improve extraction efficiency and light-emitting luminance.

Abstract: A light-emitting diode (LED) epitaxial structure includes, from bottom to up, a substrate, a first conductive type semiconductor layer, a super lattice, a multi-quantum well layer with V pits, a hole injection layer and a second conductive type semiconductor layer. The hole injection layer appears in the shape of dual hexagonal pyramid, which fills up the V pits and embeds in the second conductive type semiconductor layer. Various embodiments of the present disclosures can effectively reduce point defect density and dislocation density of semiconductor material and effectively enlarge hole injection area and improves hole injection efficiency.

Abstract: A light-emitting diode (LED) chip includes from bottom to up: a conductive substrate, a p-type nitride layer, an active layer, an n-type recovery layer, an n-type nitride layer and an n electrode, wherein, the n-type nitride layer has a nitride polarity crystal and a gallium polarity crystal, and the surfaces of the nitride polarity and the gallium polarity regions appear different in height, the n-type recovery layer surface approximate to the n-type nitride layer has consistent mixed polarity with the n-type nitride layer, and the surface far from the n-type nitride layer is a connected gallium polarity surface.

Abstract: A light-emitting diode includes a material structure of barrier in the light-emitting well region to improve restriction capacity of electron holes, improving light-emitting efficiency of the LED chip under high temperature. The LED structure includes a Type I semiconductor layer, a Type II semiconductor layer and an active layer between the both, wherein, the active layer is a multi-quantum well structure alternatively composed of well layers and barrier layers, in which, the first barrier layer is a first AlGaN gradient layer in which aluminum components gradually increase in the direction from the Type I semiconductor layer to the quantum well, and the barrier layer at the middle of well layers is an AlGaN/GaN/AlGaN multi-layer barrier layer, and the last barrier layer is a second AlGaN gradient layer in which aluminum components gradually decrease in the direction from the quantum well to the Type II semiconductor layer.