163 results about "Molecular beam epitaxial growth" patented technology

The invention provides a molecular beam epitaxy (MBE) growing method of a high-speed vertical-cavity surface-emitting laser. The method comprises the steps that deoxidation pretreatment is conducted on a GaAs substrate, and epitaxial growth of a GaAs buffer layer, a lower DBR, an active region, an oxidation confinement layer and an upper DBR is sequentially achieved; in the growth process, the active region is clamped between the upper DBR and the lower DBR, and a delta-doping method is adopted by the potential barrier middle position of the active region, wherein a doping source adopts carbon (C), and growth is stopped for a period of time under the protection of As after delta-doping is completed. By means of the method, the technical problems of reducing a threshold, increasing differential gain and reducing nonlinear gain compression are solved, and the good effects of reducing optical losses, decreasing line width and increasing output power and intrinsic bandwidth are achieved.

A method of modifying the optical properties of a processed nitride semiconductor light-emitting device initially comprises disposing the processed nitride semiconductor light-emitting device in a vacuum chamber. One or more nitride semiconductor layers are then grown by molecular beam epitaxy thereby to modify the optical properties of the processed light-emitting device. Activated nitrogen, for example from a plasma source, is supplied to the vacuum chamber during growth of the nitride semiconductor layer(s). The use of activated nitrogen reduces the growth temperature required for the growth of the nitride semiconductor layer(s), as the need for thermal activation of a nitrogen species is eliminated. Moreover, use of a growth method such as, for example, plasma-assisted MBE to grow the nitride semiconductor layer(s) allows much more precise control of their thickness and composition.

The invention discloses a spectroscopic method and a device for quickly testing type II infrared superlattice interface quality. The spectroscopic device comprises a Fourier transform infrared measuring system which has a function of step scan, a laser device which serves as a pump light source, a temperature-changing and magnetic-field-changing sample measuring system, a phrase lock amplifier which connects a detector and a circuit control panel in the Fourier transform infrared measuring system, and a wave chopper which is arranged between the temperature-changing and magnetic-field-changing sample measuring system and the laser device. With the spectroscopic device being used, the type II infrared superlattice interface quality is quickly tested through measuring the degree of attenuation of the photoluminescence intensity of type II infrared superlattices along a magnetic field. The test for infrared band In As / Ga Sb type II infrared superlattices of molecular beam epitaxy indicates that the spectroscopic method for quickly testing the type II infrared superlattice interface quality is an optical method capable of quickly and conveniently testing type II infrared superlattice interfaces. The spectroscopic method for quickly testing the type II infrared superlattice interface quality has the advantages of being lossless and sensitive, and is especially suitable for the detection of weak optical signals on the type II infrared superlattice interfaces.

A 3 group-5 group compound ferromagnetic semiconductor, comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P, wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase as a whole. The ferromagnetic semiconductor can be fabricated by a plasma-enhance molecular beam epitaxy growing method and since it shows the ferromagnetic characteristics at a room temperature, it can be applied as various spin electron devices.

In system(s) utilizing multiple molecular beams of Group V material(s) (and/or Group VI material(s)), rotary beam chopper(s)) 8 and so forth are installed in front of respective discharge port(s) of such plurality of Group V molecular beam source cell(s) 5, 6 (and/or Group VI molecular beam source cell(s)); intermittency control causing molecular beam(s)) discharged from respective molecular beam source cell(s) 5, 6 to be repeatedly blocked and discharged in periodic fashion is carried out; and mutual synchronization of such molecular beam(s)) subjected to intermittency control causes supply of respective molecular beam(s)) of multiple Group V materials (and/or Group VI materials) in sufficient quantity or quantities as necessary for crystal growth, with alloy ratio(s) within crystal(s) being efficiently controlled.

The invention discloses a molecular beam epitaxial (MBE) growth method of a Bi element regulated and controlled GaAs-based nanowire crystal structure. A Bi element is introduced as an activating agent during the growing process of nanowires in an MBE growth chamber, the ionicity of GaAs is reduced, and the formation of a nanowire zinc blende structure is promoted. The method is characterized in that the Bi evaporator source temperature is regulated during the process of nanowire growth according to the beam equivalent partial pressure of a Ga element so as to control the beam equivalent partial pressure of the Bi element and to ensure that the ratio of the beam equivalent partial pressure of the Bi element to that of the Ga element is x, and the value of x can influence the regulating and controlling ability of the Bi element to the nanowire crystal structure and influence the feature and the phase structure purity of the nanowires. The method has the benefits that the growth of the GaAs-bases nanowires with the zinc blende crystal structure can be easily realized without changing the growth process conditions of MBE, and thus the method is beneficial to the controlled growth of the GaAs-based nanowires with the wurtzite and zinc blende structure and the formation of a homogeneous heterophase heterogeneous structure of the nanowires, and provides an excellent material for preparing nanoscale photoelectronic devices.

The invention relates to a gas source molecular beam epitaxy material growth method for a component progressive transition layer, and the method comprises the steps: growing the component progressive transition layer with one-side or two-side materials of a heterojunction containing two or more types of group-V elements through employing a gas source molecular beam epitaxy growth method, employing two or more gas sources for growth, wherein a group-III beam source is solid, a beam flow is controlled through shutter switching, a group-V beam source is gaseous, and the group-V beam flow intensity or V-III ratio is adjusted through pressure or flow; and obtaining the component progressive transition layer. The component progressive transition layer obtained through the method can effectively alleviate negative effects, caused by energy band peak of a heterogeneous interface or crystal lattice and component abrupt changes in a heterojunction device, on the performance of a device, thereby facilitating the improvement of the performance of the device or the development of a novel device.

The invention belongs to the technical field of memories, and specifically discloses a two-dimensional ultrafast accurate nonvolatile memory based on a self-rectification characteristic material and apreparation method thereof. The material with a self-rectification characteristic is used for replacing the channel and tunneling layers of a traditional flash memory (Flash), and through a switchingcharacteristic of the material, a tunneling mechanism of traditional charges is replaced to realize ultrafast write-in and accurate nonvolatile memory. The preparation method comprises the followingsteps: firstly using mechanical stripping or chemical vapor deposition to obtain a two-dimensional material as a charge storage layer on a substrate, and then using molecular beam epitaxy to grow theself-rectification characteristic material CrX3 as device channels and switches. The novel memory with ultrafast write-in capacity and accurate nonvolatile characteristic can be prepared, the data storage time span between a dynamic random access memory and a flash memory is remedied, and the novel memory has great application prospects in the field of future memories.