Interfacial Modulation And Growth Process Optimization Of N-ZnO Nanorods/p-GaN Heterojunctions

Zinc oxide(ZnO)semiconductor material,with a wide direct band gap(3.37eV)and a large exciton binding energy(60meV)at room temperature,has been considered as a potential candidate material for short-wavelength optoelectronic applications,especially for UV-LED and UV-LD.However,ZnObased homo-junction has suffered from lack of reproducible and high-quality ptype materials.As an alternative approach to homojunction,n-ZnO/p-GaN heterojunction has been proposed as attractive candidates for device applications,for ZnO and GaN have the same crystal structure(wurtzite),the similar band gap and relatively small lattice mismatch(1.8%).Among themselves,the n-ZnO nanorods/p-GaN heterojunctions have attracted much attention due to their excellent photoelectric properties.The crystal quality and photoelectric properties of ZnO nanorods are one of the main factors affecting the photoelectric properties of n-ZnO nanorods/p-GaN-based devices,and their quality and properties are determined by the interfacial conditions and growth processes of ZnO/GaN heterostructures of.However,the study of ZnO nanorods grown on GaN is mainly focused on changing the GaN epitaxial parameters or ZnO growth conditions to study their effect on the photoelectric properties of ZnO/GaN heterojunctions.There is no agreement about the effect of outcrops on the structure and properties of ZnO at the interface of its surface(the interface of ZnO / GaN).In this paper,the morphological structure and optical properties of ZnO grown on the surface of ZnO were investigated by wet etching to control the dislocation of p-GaN at the interface of ZnO/GaN.The mechanism of outcrop on the growth of ZnO nanorods was further studied,and the effect of interfacecontrolled n-ZnO nanorods/p-GaN heterostructures on the growth of ZnO nanorods was studied.Growth concentration and other aspects of process optimization.The main research contents and results are as follows:1.The effect of dislocation on the surface(ZnO / GaN interface)dislocation of GaN dislocations was studied by wet etching,and the effect on the crystal quality and optical properties of ZnO nanorods was studied.Relative to the noncorrosive,corrosion 5 min,corrosion 10 min sample,when the etching time is 8 min,the ZnO nanorod arrays in the heterostructures are the smallest,the densest and the optical properties are the best.This is because the dislocations in the pGaN with an etch time of 8 min are substantially all out of the interface at which the ZnO grown on it is easily adhered to form more nucleation seeds and the staggered stencil The epitaxial growth of ZnO crystals is promoted,and the ZnO is more fine and uniform,and the crystal quality is high,which leads to the better optical properties of heterogeneous structure samples.2.The effect of interface outcrop on the growth of ZnO nanorods was investigated by studying the evolution process of ZnO nanorods grown on GaN before and after wet etching.The results show that the interface by etching has a good effect on the nucleation and growth of ZnO nanorods,which can make the nucleation and growth time advance,because the dislocation outcrop of the interface is more lively than other positions ZnO is adsorbed and aggregated at the dislocation head,which is favorable for the nucleation of ZnO.3.The effects of these parameters on the crystal structure and optical properties of the ZnO nanorods were investigated by changing the growth temperature and the growth concentration.The results show that:(1)The growth temperature of 95 ? can help to obtain excellent ZnO nanorods,while the low(65 ?)or too high(125 ?)temperature is unfavorable to the growth of ZnO nanorods.This is because the thermal growth of ZnO is an endothermic process,low temperature is not conducive to the progress of the reaction.In addition,the low temperature leads to the reaction rate is too low,is not conducive to the crystallization of ZnO nanorods uniformity;and high temperature lead to the reaction rate is too fast,the reactants consumed too fast in the middle and late growth,the remaining reactants are not sufficient to grow a relatively complete ZnO nanorods.0.05 mol/L growth concentration was helpful to obtain excellent ZnO nanorods.The concentration of low(0.02 mol/L)or too high(0.10 mol/L)was not favorable for the growth of ZnO nanorods.The direct consequence of the low concentration is that the reactant concentration is too low to achieve full coverage of the ZnO nanorods,and in the reactants of the six Methylamine reaction decomposition of ammonia,OH-concentration is too high will limit the growth of ZnO nanorods.