| Nano-laser refers to laser light emitted by nano-materials such as nano-wires as a resonant cavity under light or electrical excitation.The size of a laser emitting a nano-laser is often only hundreds of microns or even tens of microns,and the diameter is even on the order of nanometers.Nano-laser future films display important components in the fields of integrated optics,optical computing,information storage,and nano-analysis,and have important application prospects in industrial,military,and medical fields.As a one-dimensional direct band gap semiconductor material,GaAs nanowires/nanowire arrays have the characteristics of high surface area-volume ratio,quantum size effect,and good crystallinity of one-dimensional materials,while retaining the high carriers of GaAs bulk materials.The advantages of mobility,high electron saturation rate,and high luminous efficiency are the materials of choice for preparing nano-lasers.However,due to the requirements of nano-lasers in terms of light emission and integration,requirements for the verticality,density,crystal quality,and optical performance of GaAs nanowires/nanowire arrays are required.This paper mainly researches the preparation process of GaAs nanowires.Through the design and experimental research of the substrate processing process and growth process in the preparation process,the optimal process flow is obtained.Prepare GaAs nanowires / nanowire arrays according to the optimal process conditions and study their morphology and physical characteristics.The main research contents include the following:?1?GaAs nanowires are prepared by MBE autocatalytic process.In order to meet the application requirements of nano lasers and improve the verticality,density,crystalline quality and optical performance of nanowires,we have designed HF substrates with different concentrations and completely etched.Two kinds of substrate treatment schemes are naturally oxidized in order to improve the verticality and density of nanowires.The droplet deposition time,V/III beam current ratio,and growth temperature are designed in the nanowire growth process in order to improve the verticality,density,crystal quality,and optical performance of the nanowires.?2?Carry out experiments according to the design plan,and use different concentrations of HF acid to etch the substrate,and grow GaAs nanowires after etching.GaAs nanowires are grown on substrates that were naturally oxidized for different days after being completely etched.The experimental results have shown that when the etching concentration is 1:10 and the natural oxidation time is 20 days,the verticality and density of the nanowires are significantly improved,which proves the feasibility of the scheme.Ga droplets are deposited using different droplet deposition times.The contact angle of the Ga droplets is close to 90° when the deposition time is 30?35 s,and the density of the Ga droplets is effectively increased.When the V/III beam ratio is 20 ? 25,the nanowireverticality is improved and the crystal quality is good.When the growth temperature is590?610 ?,the verticality,crystal quality and optical properties of the nanowires are improved.This study lays the foundation for the preparation of GaAs nanowires / nanowire arrays?3?The GaAs nanowires/nanowire arrays are prepared using the best process conditions,and the morphology of the nanowires is characterized.The vertical rate of the nanowires was close to 100%,and the density is higher than 1 × 109 cm-2.The structure of the nanowires is characterized.The nanowires are WZ/ZB mixed-phase structures and almost no defects such as stacking faults.The optical properties of the nanowires are characterized.The two emission peaks of the nanowires emit light at 818 nm and 830 nm,which are free exciton emission and II-type emission,respectively,and have good emission intensity.The test results show that the prepared GaAs nanowires/nanowire arrays meet the application requirements of nano lasers,laying a foundation for the application of GaAs nanowires in nano-lasers. |
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