Zinc oxide is an important functional and navel material of Ⅱ-Ⅵ wide bandgap semiconductor.ZnO thin films has a direct bandgap of 3.37 eV with exciton binding energy of 60 meV

and is being considered as a new kind of rapidly developing photoelectric material follows after ZnSe

GaN based materials

and showing enormous developing prospect for applications in the field of LEDs

LDs

and UV detectors.Various growth techniques of ZnO thin films have been extensively studied

including

magnetron sputtering

PLD

MOCVD

MBE

spray pyrolysis

and sol-gel methods

etc.The sol-gel process is regarded as a powerful and cost-effective technique for fabricating nano-materials

and has been successful used for preparation of various kinds of oxide films

such as PT

PZT

PLT

PLZT

SrTiO

3

and ZnO films

etc.However

there are few papers on ZnO nanofilms prepared by sol-gel process and served as the buffer layer for SiC thin film grown on Si substrate by LP CVD.The research results on those issues will be introduced.ZnO nanofilms with highly c-axis orientation were prepared by sol-gel process using zinc acetate(Zn(CH

3

COO)

2

·2H

2

O)as starting material.A colorless transparent

homogeneous

stable and undoped ZnO sols with a concentration of 0.2～0.5 mol/L were obtained and served as the coating solutions.Si(100)

Si(111)and c-plane sapphire were used as substrate.The wet films were spin-coated on substrate at a speed of 3000 r/min for about 40 seconds

and pre-heated at 150℃ for 30 minutes after each coating

and post-heated in air at different temperature from 500～900℃ for an hour.The prepared ZnO nanofilms are colorless

transparent

homogeneous and crack-free

mirror-like films.The microstructures and the surface morphology of ZnO nanofilms are investigated by XRD

AFM

SEM

Hall analyzer

and ellipsometer etc.The grain size

roughness

refractive index and thickness of ZnO nanofilms were measured.The results showed that the orientation of ZnO nanofilm samples are highly caxis oriented

and it was a surprised that the ZnO(002)diffraction peak of the sample prepared on Si(100)substrate and post-heated at 600℃ is evidently shift from the normal position 2θ=34.42°to the lower angle direction at 2θ=32.90°

the shift value is-1.52°

and the strength of this peak is the strongest

and also in the left side of this peak

i.e.2θ=32.64°

there is an unknown diffraction peak.This can be attributed to the microstructure changes occurred in ZnO nanofilm samples.The strength of ZnO(002)diffraction peak is decreased with increasing post-heated temperature from 600℃ to 900℃.The surface morphology of ZnO nanofilm samples post-heated at different temperature is quite difference

some are similar to the quantum dots

and others are quite flat.Two kinds of SiC thin films had been grown on n-type Si(100)substrate using undoped ZnO nanofilm as buffer layer by low pressure chemical vapor deposition.The structure and electrical properties of SiC/ZnO/Si(100)samples had been measured and analyzed.