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研究了用MOCVD法在蓝宝石(Al2O3)(0001)和(1120)衬底上制备ZnO薄膜时的生长特性.详细研究了采用Al2O3(0001)衬底时生长温度与压力的影响.由于存在比较大的晶格失配,一般容易得到ZnO纳米结晶,不容易获得既平坦且质量又好的ZnO薄膜.生长温度对薄膜衬底界面的生长模式有很大的影响;而生长压力对ZnO纳米结晶的形状有决定性作用.通过适当控制生长温度及压力,可以得到ZnO薄膜或不同形状的纳米结构.当采用Al2O3(1120)衬底时,由于晶格失配较小,能保持平坦层状生长,临界膜厚远远大于采用Al2O3(0001)衬底的结果.在Al2O3(1120)衬底上制作了ZnO/MgZnO量子阱并研究了其光学特性.观察到了量子化能级间以及在载流子间的跃迁引起的发光.由压电效应引起的内建电场约为3×105V/cm.同时发现采用低温低压生长可以增大ZnO中受主杂质浓度,有利于获得p型ZnO.
The growth characteristics of ZnO films prepared by MOCVD on (0001) and (1120) substrates were investigated. The effects of growth temperature and pressure on the growth of Al2O3 (0001) substrates were investigated in detail. Of the lattice mismatch, the ZnO nanocrystal is generally easy to obtain, it is not easy to obtain both flat and good quality ZnO film growth temperature on the film substrate interface growth mode has a great impact; and growth pressure on the ZnO nanocrystalline Shape is decisive.With proper control of growth temperature and pressure, ZnO thin films or nanostructures with different shapes can be obtained.When Al2O3 (1120) substrate is used, it can maintain flat lamellar growth due to the smaller lattice mismatch, The film thickness is much larger than that of the Al2O3 (0001) substrate.The ZnO / MgZnO quantum wells were fabricated on the Al2O3 (1120) substrate and the optical properties were investigated.It was observed that the quantum energy levels and the inter- The built-in electric field caused by the piezoelectric effect is about 3 × 10 5 V / cm, and at the same time it is found that the low-temperature and low-pressure growth can increase the acceptor impurity concentration in ZnO, which is favorable for obtaining p-type ZnO.