CN101275073B

CN101275073B - Preparation for ZnO quantum dot

Info

Publication number: CN101275073B
Application number: CN2007100714425A
Authority: CN
Inventors: 黄靖云; 陈玲; 叶志镇
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2007-09-26
Filing date: 2007-09-26
Publication date: 2010-07-21
Anticipated expiration: 2027-09-26
Also published as: CN101275073A

Abstract

The present invention provides a preparing method of ZnO quantum dot. Firstly, processing surface treatment to a substrate, then forming a layer nano-sphere assembled by itself by czochralski method in deionized water, the nano-sphere is used as a template for preparing ZnO quantum dot; further, depositing a layer ZnO film which thickness is 5nm-50nm by electron beam evaporation under the conditions of temperature between 25-100 DEG C, 10<-4>-10<-6> Torr vacuum; finally, dipping in toluol, and vibrating 2-5 min by ultrasonic to remove the nano-sphere in the template. The ZnO quantum dot prepared by the method has large growth area, regular arrangement, even distribution. The preparing method simply, economically and effectively produces ZnO quantum dot having larger range, and order. The ZnO oxide semiconductor energy gap is wide, direct wide band gap is transmitted, and exciton binding energy is large, the ZnO quantum dot material becomes expectations of high quantum dot laser and nan0-laser by adding the quantum confinement effect of the quantum dot.

Description

A kind of preparation method of ZnO quantum dot

Technical field

The present invention relates to the preparation of semiconductor nano material and device, relate to a kind of preparation method of ZnO quantum dot specifically.

Background technology

ZnO has good blue light and ultraviolet light emission performance as a kind of wide bandgap semiconductor, and high exciton bind energy and the emission of low threshold value optical pumping realize stimulated emission efficiently easily.The three-dimensional quantum effect of semiconductor-quantum-point causes the available state density and the energy generation noticeable change of system current carrier, has the exciton bind energy of bigger band-gap energy and Geng Gao, is easier to as ultraviolet semiconductor luminotron and laser apparatus.The preparation method of ZnO quantum dot is mainly wet chemistry method, but the requirement of this method has a large amount of solvents, kinds of processes step and long growth time, and it is uncontrollable to grow, and has reported recently with mocvd method at Si/SiO ₂Growing ZnO quanta dots on the substrate, also useful pulse laser method and annealing method have also obtained the ZnO quantum dot, but the size of the ZnO quantum dot of preparation and distribution all are at random, the limited energy level disperse of uneven quantum dot within limits, the breaking up of the branch of energy causes very big luminous broadening, so the performance of the quantum dot laser of development is far from reaching so superior as the theory prophesy at present.Therefore improve the distribution of sizes of quantum dot uniformity coefficient, to increase that effective quantum counts out be the research direction that realizes nano laser.

Summary of the invention

The preparation method who the purpose of this invention is to provide a kind of ZnO quantum dot.

The preparation method of ZnO quantum dot: at first substrate is carried out surface treatment, in deionized water, form the nanometer ball of individual layer self-assembly then, as the used template of preparation ZnO quantum dot with crystal pulling method; Then between 25～100 ℃, vacuum tightness is 10 ^-4～10 ^-6Under the condition of Torr, by the thick ZnO film of electron-beam evaporation one deck 5nm～50nm; Last in toluene, soak and ultrasonic vibration 2～5min removes the nanometer ball in the template and gets final product.

Treatment process when described substrate is Si is 1: 1 H in volume ratio at first using the alcohol ultrasonic cleaning then ₂SO ₄+ H ₂O ₂Boiling 10～30min in the mixing solutions, then is 3: 1 NH in volume ratio ₄OH+H ₂O ₂Ultrasonic vibration 30～60min in the mixing solutions, temperature is 80～100 ℃.The material of nanometer ball is a polystyrene, and the diameter of ball is 100nm～1000nm.Substrate is silicon, sapphire or conductive glass.

Advantage of the present invention is:

1. the ZnO quantum dot of present method preparation can be realized controllable growth by the size and the sedimentary thickness that change employed nanometer ball diameter in the template.

The ZnO quantum dot of present method preparation improved the quantum dot distribution of sizes uniformity coefficient, increased effective quantum and counted out, tentatively solved the problem of quantum dot laser development.

3. present method is not used any activator, the ZnO quantum dot quality that makes is good, and it is even to add size, so in the test of PL spectrum, when the diameter of quantum dot reaches tens nanometers, still can observe tangible blue shift phenomenon, reduce the manufacture difficulty of nanometer laser device dimensionally.

4. the ZnO quantum dot good stability of Fa Ming preparation tests not changing after one month.

5. preparation method's device procedures of Fa Ming ZnO quantum dot is simple, economical and effective.

Description of drawings

Fig. 1 (a) is the synoptic diagram of the individual layer self-assembled nanometer ball of formation

Fig. 1 (b) is the synoptic diagram of electron-beam evaporation layer of ZnO film

Fig. 1 (c) is a side elevational view of removing the synoptic diagram of the ZnO quantum dot that forms behind the bead

Fig. 1 (d) is a vertical view of removing the synoptic diagram of the ZnO quantum dot that forms behind the bead

Fig. 2 is SEM (field emission scanning electron microscope) figure of the template of individual layer nanometer bead

Fig. 3 is the SEM figure after deposition layer of ZnO on the template

Fig. 4 is the SEM figure of the ZnO quantum dot that makes of this preparation method

Fig. 5 is PL (photoluminescence spectrum) spectrum of ZnO quantum dot of the present invention.

Embodiment

Below further specify the preparation method of ZnO quantum dot of the present invention by example in conjunction with synoptic diagram, Fig. 1 is the preparation process synoptic diagram.

Embodiment 1

At first to 1 * 1cm ²The low-mix n-Si sheet ultrasonic cleaning of (100) face of size is 1: 1 H then in volume ratio ₂SO ₄+ H ₂O ₂Boiling in the mixing solutions ten minutes, then is 3: 1 NH in volume ratio ₄OH+H ₂O ₂Ultrasonic vibration 30min in the mixing solutions, temperature is 80 ℃, purpose is the planeness for the wetting ability of improving substrate and surface, get 2-3 with dropper then and drip that concentration is 10%, diameter is the suspension liquid of the pipe/polyhenylethylene nano ball of 600nm, drop in the silicon chip surface of having handled, leave standstill the covering entire substrate that makes the bead even compact, then the substrate that is paved with ball being immersed in the deionized water slowly.At this moment on the substrate and the water surface, formed the bead of individual layer hexagonal solid matter, for above the bead that prevents water surface deposits to when substrate puts forward once more, in deionized water, splash into one or two sodium dodecyl sulfate solution, changed the surface tension of water, the bead that is suspended in the water surface scatters rapidly, proposes substrate then, dry, as shown in Figure 1a, the nanometer ball template of six side's solid matters of individual layer self-assembly has just been carried out like this, and Fig. 2 is the SEM figure of individual layer nanometer bead template.

Secondly, shown in Fig. 1 b, will have the substrate of template to be fixed on and put on the slide glass on the reaction chamber specimen holder, substrate is desired the deposition table placed face down, substrate is not heated, and reaction chamber vacuum tightness is evacuated to 4.5 * 10 ^-6Torr in the deposition process, feeds O ₂, the air pressure of reaction chamber is 3.0 * 10 ^-5Torr, depositing time are 4min, and thickness is 30nm, and Fig. 3 is the SEM figure of the template behind the deposition layer of ZnO film.

At last the template of deposition behind the ZnO put into toluene and soak ultrasonic vibration 2min after hour, because between PS ball and the substrate is molecular force, and be the chemical bond combination between the ZnO of electron beam deposition and the substrate, so the PS ball is removed after vibrating with the ZnO film that is deposited on the ball surface, kept and see through the sedimentary ZnO quantum dot in space, as Fig. 1 c, shown in the d, Fig. 4 is the SEM figure of the ZnO quantum dot of preparation.

The light at room temperature electroluminescent properties test of ZnO quantum dot of the present invention, excitation light source is the xenon lamp of wavelength 310nm, the ultra-violet light-emitting peak is 3.35eV, than ZnO film tangible blue shift is arranged, as shown in Figure 5.

Embodiment 2

At first substrate is 1 * 1cm ²Low-mix n-Si sheet size, (100) face, it is carried out similar face handles, working concentration is that 10% diameter is the suspension liquid of the monodisperse system of 100nm nanometer ball, forms the nanometer ball of individual layer self-assembly equally with crystal pulling method, as the used template of preparation ZnO quantum dot; Be 10 at 100 ℃, vacuum tightness then ^-6Under the condition of Torr, by the thick ZnO film of electron-beam evaporation one deck 5nm; Last in toluene, soak and ultrasonic vibration 2min removes the nanometer ball in the template and gets final product.

Embodiment 3

At first substrate is 1 * 1cm ²Size, the low-mix n-Si sheet of (100) face, it is carried out similar face handles, working concentration is that 10% diameter is the suspension liquid of monodisperse system of the nanometer ball of 1000nm, forms the nanometer ball of individual layer self-assembly equally with crystal pulling method; Then at room temperature, vacuum tightness is 10 ^-4Under the condition of Torr, by the thick ZnO film of electron-beam evaporation one deck 50nm; Last in toluene, soak and ultrasonic vibration 5min removes the nanometer ball in the template and gets final product.

Claims

1. the preparation method of a ZnO quantum dot is characterized in that: at first form the nanometer ball of individual layer self-assembly with crystal pulling method on surface-treated substrate, as the used template of preparation ZnO quantum dot; Then in room temperature～100 ℃, vacuum tightness is 10 ^-4～10 ^-6Under the condition of Torr, by the thick ZnO film of electron-beam evaporation one deck 5nm～50nm; Last in toluene, soak and ultrasonic vibration 2～5min removes the nanometer ball in the template and gets final product; Described nanometer ball is a polystyrene spheres, and the diameter of ball is 100nm～1000nm.

2. by the preparation method of the described a kind of ZnO quantum dot of claim 1, it is characterized in that the treatment process when described substrate is Si is ultrasonic cleaning in alcohol at first, be 1: 1 H then in volume ratio ₂SO ₄+ H ₂O ₂Boiling 10～30min in the mixing solutions, then is 3: 1 NH in volume ratio ₄OH+H ₂O ₂Ultrasonic vibration 30～60min in the mixing solutions, temperature is 80～100 ℃.

3. by the preparation method of the described a kind of ZnO quantum dot of claim 1, it is characterized in that described substrate is silicon, sapphire or conductive glass.