Nanoscale Potential Fluctuations in (GaMn)As/GaAs Heterostructures: From Individual Ions to Charge Clusters and Electrostatic Quantum Dots

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• 作者：A. P. Wijnheijmer ; O. Makarovsky ; J. K. Garleff ; L. Eaves ; R. P. Campion ; B. L. Gallagher ; P. M. Koenraad
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：December 8, 2010
• 年：2010
• 卷：10
• 期：12
• 页码：4874-4879
• 全文大小：448K
• 年卷期：v.10,no.12(December 8, 2010)
• ISSN：1530-6992

文摘

During growth of the dilute p-type ferromagnetic semiconductor Ga_1−xMn_xAs, interstitial manganese, Mn_ip>2+p>, is formed when x exceeds 2%. The double donor Mn_ip>2+p> compensates the free holes that mediate ferromagnetism. Annealing causes out-diffusion of these interstitials, thereby increasing the Curie temperature. Here, we use cross sectional scanning tunneling microscopy and spectroscopy to visualize the potential landscape which arises due to the clustering of Mn_ip>2+p> in annealed p−i−n (GaMn)As−GaAs double barrier heterostructures. We map the local minima in the potential landscape, link them to clusters of individual Mn_ip>2+p> ions, and show that the ions are doubly charged.p>

Keywords:

Gallium manganese arsenide; interstitial manganese; cross-sectional scanning tunneling microscopy; cross-sectional scanning tunneling spectroscopy; heterostructure band profiling; electrostatic quantum dot