tailieunhanh - Báo cáo hóa học: " Growth of InAs Quantum Dots on Germanium Substrate Using Metal Organic Chemical Vapor Deposition Technique"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Growth of InAs Quantum Dots on Germanium Substrate Using Metal Organic Chemical Vapor Deposition Technique | Nanoscale Res Lett 2010 5 31-37 DOI s11671-009-9439-y NANO EXPRESS Growth of InAs Quantum Dots on Germanium Substrate Using Metal Organic Chemical Vapor Deposition Technique Tanuj Dhawan Renu Tyagi Rajesh Kumar Bag Mahavir Singh Premila Mohan T. Haldar R. Murlidharan R. P. Tandon Received 28 April 2009 Accepted 9 September 2009 Published online 19 September 2009 to the authors 2009 Abstract Self-assembled InAs quantum dots QDs were grown on germanium substrates by metal organic chemical vapor deposition technique. Effects of growth temperature and InAs coverage on the size density and height of quantum dots were investigated. Growth temperature was varied from 400 to 450 C and InAs coverage was varied between and monolayers MLs . The surface morphology and structural characteristics of the quantum dots analyzed by atomic force microscope revealed that the density of the InAs quantum dots first increased and then decreased with the amount of InAs coverage whereas density decreased with increase in growth temperature. It was observed that the size and height of InAs quantum dots increased with increase in both temperature and InAs coverage. The density of QDs was effectively controlled by growth temperature and InAs coverage on GaAs buffer layer. Keywords Quantum dots Ge substrate InAs Self-assembled Introduction Self-assembled InAs quantum dots QDs grown on GaAs substrate have generated a momentous interest in the last T. Dhawan R. P. Tandon El Department of Physics Astrophysics University of Delhi Delhi 110007 India e-mail ram_tandon@ R. Tyagi R. K. Bag M. Singh P. Mohan T. Haldar R. Murlidharan Solid State Physics Laboratory Lucknow Road Timarpur Delhi 110054 India few years due to their potential applications in QD lasers 1 2 and infrared photodetectors 3 4 . QD lasers have demonstrated superior characteristics such as ultra-low-threshold current densities 5 6 ultra-high-temperature stability 7 very high differential efficiency 8 .