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/金属的混合结构作为一种新的量子功能材料，传统的生长技术是没有用的。异质界面必须控制在单层精度。我们设计并制作了一种新的OMVPE系统反应器结构，该反应器具有源气体的快速切换和低压立式反应器中的相应压力平衡。生长了具有单层水平InGaAs和不同源气体开关模式的InP/InGaAs/InP异质界面结构，主要用X-射线衍射研究了异质界面结构。利用同步辐射进行X射线CTR散射和干涉。还在InP中制备了δ掺杂ErP结构，并通过荧光探测EXAFS和X射线CTR散射阐明了ErP的层结构甚至晶体结构。ErP层被发现是岩盐结构，通过这两种技术和Er分布（生长和退火后）被确定为一个单层水平。从Er原子周围的局域结构的生长温度依赖性可以非常清楚地得出结论，光致发光强度对生长温度的强烈依赖性是由Er原子周围的局域结构决定的，即，这种新的生长体系的多功能开关模式使液滴异质外延成为可能，成功地在InP（001）面上制备了InAs量子点，并在1.5 μ m范围内发射，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.