内嵌InAs量子点的δ掺杂GaAs/Al_xGa_(1-x)As二维电子气特性分析

Properties of δ doped GaAs/Al_xGa_(1-x)As 2DEG with embedded InAs quantum dots

采用分子束外延技术对δ掺杂GaAs/AlxGa1 xAs二维电子气(2DEG)样品进行了生长.在样品生长过程中,分别改变掺杂浓度(Nd)、空间隔离层厚度(Wd)和AlxGa1 xAs中Al组分(xAl)的大小,并在双温(300 K,78 K)条件下对生长的样品进行了霍尔测量;结合测试结果,分别对Nd,Wd及xAl与GaAs/AlxGa1 xAs 2DEG的载流子浓度和迁移率之间的关系规律进行了细致的分析讨论.生长了包含有低密度InAs量子点层的δ掺杂GaAs/AlxGa1 xAs2DEG样品,采用梯度生长法得到了不同密度的InAs量子点.霍尔测量结果表明,随着InAs量子点密度的增加,GaAs/AlxGa1 xAs 2DEG的迁移率大幅度减小,实验中获得了密度最低为16×108/cm2的InAs量子点样品.实验结果为内嵌InAs量子点的δ掺杂GaAs/AlxGa1 xAs 2DEG的研究和应用提供了依据和参考.

Theδ-doped GaAs/Alx Ga1？x As 2DEG samples are grown with molecular beam epitaxy. In this process, the doping concentration （Nd）, spatial isolation layer thickness （Wd） and Al component of AlxGa1？xAs （xAl） are changed separately. Then Hall measurements on the samples are made in the two temperature conditions （300 and 78 K）. According to the test results, the relationships of Nd, Wd and xAl to the carrier density and mobility of GaAs/Alx Ga1？x As 2DEG are discussed respectively. Theδ-doped GaAs/Alx Ga1？x As 2DEG with embedded InAs quantum dot samples are grown, and InAs quantum dots with different densities are grown with gradient growth method. The Hall measurement results show that the mobility of GaAs/Alx Ga1？x As 2DEG greatly decreases with density of InAs quantum dots steadily increasing. In experiments, the lowest density of 16 × 108/cm2 InAs quantum dot sample is obtained. The experimental results can provide a reference for the study and application ofδ-doped GaAs/Alx Ga1？x As 2DEG with embedded InAs quantum dots.