DEVELOPMENT OF FABRICATION SYSTEM FOR NEW QUANTUM FUNCTIONAL MATERIALS OF SEMICONDUCTOR/INSULATOR/METAL HYBRID STRUCTURES

为了实现半导体/绝缘体/金属这种新型量子功能材料的混合结构，传统的生长技术是行不通的。异质界面必须控制在单层精度。在OMVPE系统中，我们设计并制造了一种新的反应器结构，在低压垂直反应器中实现了气源的快速切换和相应的压力平衡。为了测试新生长体系的基本性能，我们生长了单层InGaAs和不同源气体开关模式的InP/InGaAs/InP，主要通过x射线CTR散射和同步辐射干涉研究了其异质界面结构，制备了InP中掺杂δ的ErP结构，并通过荧光检测EXAFS和x射线CTR散射分析了ErP的层状结构甚至晶体结构。两种技术均发现ErP层为岩盐结构，并确定了生长时和退火后的Er分布为单层水平。从Er原子周围局部结构对生长温度的依赖性可以很清楚地得出光致发光强度对生长温度的强依赖性是由Er原子周围的局部结构决定的，即锌闪锌矿结构给出了较高的光致发光强度，岩盐结构几乎减弱了光致发光强度。新生长体系的多种开关模式使得在InP (001)-just表面上成功制备了InAs量子点的液滴异质外延，并显示出在1.5 μ m区域的发射，这对光纤通信具有重要意义。

To realize such a hybrid structure as smiconductor/insulator/metal for a new quantum functional materials, conventional growth techniques are of no use. The hetero-interface must be controlled to one monolayr accuracy. We designed and fabricated a new reactor structure in OMVPE system with very quick switching of source gases and correpondong pressure balance in the low-pressure vertical reactor.To test the basic capability of the new growth system, InP/InGaAs/InP with monolayr level InGaAs and with different switching modes of source gases were grown and the heterointerface structures were investigated mainly by the X-ray CTR scattering and interference using synchrotron radiation.delta-doped ErP structures in InP were also fabricated and the layr structure and even the crystal structure of the ErP were elucidated by fluorescence-detected EXAFS and X-ray CTR scattering. The ErP layr was found to be the rocksalt structure by both techniques and the Er distribution (as-grown and after anealing) was determined to one monolayr level. From the growth temperature dependence of the local structures around Er atoms it was very clearly concluded that the strong dependence of the photo-luminescecce intensity on the growth temperature is determined by the local structure around the Er atoms, i.e., zincblende strucrtre gives a high intensity and the rocksalt structure almost diminshes the luminescene.The versatile switching modes of the new growth system enabled the droplet hetero-epitaxy by which InAs quantum dots on InP (001)-just surface were successfully fabricated and showed emission in the 1.5mum-region which is important for the optical fiber communication.