An epitaxial structure of a nonpolar AlGaN-based deep-ultraviolet (DUV) photoelectric detector and a preparation method thereof are provided. The epitaxial structure of the nonpolar AlGaN-based DUV photoelectric detector includes a nonpolar AlN buffer layer, a nonpolar Al.sub.0.15Ga.sub.0.85N buffer layer, and a nonpolar Al.sub.0.7Ga.sub.0.3N epitaxial layer that are sequentially grown on a LaAlO.sub.3 substrate. The LaAlO.sub.3 substrate takes a (100) plane as an epitaxial plane, and AlN[11-20] as an epitaxial growth direction. With the LaAlO.sub.3 substrate, the epitaxial structure reduces dislocations and stresses between the substrate and the epitaxial buffer layer. By designing two AlGaN epitaxial buffer layers with different components, the epitaxial structure reduces a dislocation density and a surface roughness of the nonpolar AlGaN epitaxial layer, further accelerates photoresponse and detectivity of the detector, and enhances overall performance of the nonpolar AlGaN-based DUV photoelectric detector.

A method of fabricating multijunction solar cell including an upper solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a lower solar subcell disposed below the upper solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the upper and lower solar subcells and having a graded lattice constant that matches the upper first subcell on a first side and the second solar subcell on the second side opposite the first side, and having a fifth band gap that is greater than the second band gap of the upper solar subcell.

The invention relates in particular to a method for producing subsequent patterns in an underlying layer (120), the method comprising at least one step of producing prior patterns in a carbon imprintable layer (110) on top of the underlying layer (120), the production of the prior patterns involving nanoimprinting of the imprintable layer (110) and leave in place a continuous layer formed by the imprintable layer (110) and covering the underlying layer (120), characterized in that it comprises the following step: at least one step of modifying the underlying layer (120) via ion implantation (421) in the underlying layer (120), the implantation (421) being carried out through the imprintable layer (110) comprising the subsequent patterns, the parameters of the implantation (421) being chosen in such a way as to form, in the underlying layer (120), implanted zones (122) and non-implanted zones, the non-Implanted zones defining the subsequent patterns and having a geometry that is dependent on the prior patterns.

A method for producing a semiconductor layer sequence is disclosed. In an embodiment the includes growing a first nitridic semiconductor layer at the growth side of a growth substrate, growing a second nitridic semiconductor layer having at least one opening on the first nitridic semiconductor layer, removing at least pail of the first nitridic semiconductor layer through the at least one opening in the second nitridic semiconductor layer, growing a third nitridic semiconductor layer on the second nitridic semiconductor layer, wherein the third nitridic semiconductor layer covers the at least one opening at least in places in such a way that at least one cavity free of a semiconductor material is present between the growth substrate and a subsequent semiconductor layers and removing the growth substrate.

One aspect of the present invention is a double sided hybrid crystal structure including a trigonal Sapphire wafer containing a (0001) C-plane and having front and rear sides. The Sapphire wafer is substantially transparent to light in the visible and infrared spectra, and also provides insulation with respect to electromagnetic radio frequency noise. A layer of crystalline Si material having a cubic diamond structure aligned with the cubic <111> direction on the (0001) C-plane and strained as rhombohedron to thereby enable continuous integration of a selected (SiGe) device onto the rear side of the Sapphire wafer. The double sided hybrid crystal structure further includes an integrated III-Nitride crystalline layer on the front side of the Sapphire wafer that enables continuous integration of a selected III-Nitride device on the front side of the Sapphire wafer.

An InGaN/GaN multiple quantum well blue light detector- includes: a Si substrate, an AlN/AlGaN/GaN buffer layer, a u-GaN/AlN/u-GaN/SiN.sub.x/u-GaN buffer layer, an n-GaN buffer layer, an InGaN/GaN superlattice layer and an InGaN/GaN multiple quantum well layer in sequence from bottom to top. The multiple quantum well layer has a groove and a mesa, the mesa and the groove of the multiple quantum well layer are provided with a Si.sub.3N.sub.4 passivation layer. The passivation layer in the groove is provided with a first metal layer electrode with a semicircular cross section, and the passivation layer on the mesa is provided with second metal layer electrode.

A photovoltaic device including a single junction solar cell provided by an absorption layer of a type IV semiconductor material having a first conductivity, and an emitter layer of a type III-V semiconductor material having a second conductivity, wherein the type III-V semiconductor material has a thickness that is no greater than 50 nm.

A photovoltaic device including a single junction solar cell provided by an absorption layer of a type IV semiconductor material having a first conductivity, and an emitter layer of a type III-V semiconductor material having a second conductivity, wherein the type III-V semiconductor material has a thickness that is no greater than 50 nm.

A method for making a photovoltaic device is provided that includes the steps of providing a silicon substrate having a complementary metal-oxide semiconductor (CMOS); bonding a first layer of silicon oxide to a second layer of silicon oxide wherein the bonded layers are deposited on the silicon substrate; and forming a III-V photovoltaic cell on a side of the bonded silicon oxide layers opposite the silicon substrate, wherein when the III-V photovoltaic cell is exposed to radiation, the III-V photovoltaic cell generates a current that powers a memory erasure device to cause an alteration of a memory state of a memory cell in an integrated circuit.

A semiconductor wafer comprising a substrate; a first AlGaN layer on the substrate; a second AlGaN layer on the first AlGaN layer; a GaN layer on the second AlGaN layer; and a plurality of crystalline GaN islands between the first and second AlGaN layers.