论文部分内容阅读
通过MOCVD方法生长的ZnO薄膜一般为富锌生长,呈n型电导,要想得到高阻或低阻p-ZnO薄膜需要对其进行掺杂施主或受主杂质。主要研究在生长过程中通过NH_3对ZnO薄膜进行氮掺杂的情况,利用优化生长条件,即生长温度为610℃,Ar气(携带DEZn)流量为4 sccm,O_2流量为120 sccm,N_2流量为600 sccm,得到在NH_3流量为80 sccm时生长样品的结晶质量最高,在掺杂薄膜中NH_3流量高于或低于80 sccm时,样品的表面形貌都将变差,只有在80 sccm时表面粗糙度最低晶粒最小,表明该流量下获得的样品表面较光滑致密。所以80 sccmNH_3流量为在R面蓝宝石上生长<110>取向ZnO薄膜的最佳掺杂流量。Hall测量结果表明,NH_3流量为50 sccm的样品电导呈弱p型,电阻率为102Ω·cm,空穴载流子浓度为+1.69×10~(16)cm~(-3),迁移率为3.6cm~2·V~(-1)·s~(-1);当NH_3流量增加时样品的电导呈n型,电阻率最高达10~8Ω·cm,我们认为与进入ZnO薄膜的H的量有关,并对其变化机理进行了详细的分析。
The ZnO thin films grown by the MOCVD method are generally zinc-rich and n-type conductivity. To obtain a high-resistance or low-resistance p-ZnO thin film, it is necessary to doping the donor or acceptor impurity. The research mainly focuses on the nitrogen doping of ZnO thin films by NH_3 during the growth process. The optimized growth conditions are that the growth temperature is 610 ℃, the flow rate of Ar gas (carrying DEZn) is 4 sccm, the O_2 flow rate is 120 sccm, the flow rate of N 2 is 600 sccm, the crystal quality of the grown sample is the highest when the flow rate of NH 3 is 80 sccm. When the flow rate of NH 3 in the doped film is higher or lower than 80 sccm, the surface morphology of the sample will deteriorate. Only when the surface is 80 sccm The smallest grain roughness of the smallest, indicating that the sample obtained under this flow smoother and more compact. Therefore, the flow rate of 80 sccmNH_3 is the optimal doping flux of <110> -oriented ZnO thin films grown on R-sapphire. The Hall measurements show that the conductivity of samples with NH_3 flow rate of 50 sccm is weak p-type, the resistivity is 102Ω · cm and the hole carrier concentration is + 1.69 × 10 ~ (16) cm ~ (-3) 3.6cm ~ 2 · V -1 · s ~ (-1). When the NH_3 flow rate increases, the conductivity of the sample is n-type and the resistivity is up to 10 ~ 8Ω · cm. Quantity, and analyzed its changing mechanism in detail.