Towards Quantum Computing: A Hybrid Approach That Will Unleash a Plethora of New QD Nanostructures, Bringing Us a Step Further to Laterally Coupled QDs
© to the authors 2009
Received: 27 May 2009
Accepted: 2 June 2009
Published: 12 June 2009
Kimberly Sablon, Zhiming Wang and Gregory Salamo (who leads the atom manipulation MRSEC facility at the University of Arkansas) and other co-authors have taken lateral ordering of QDs to a whole new level and have devoted much effort to controlling the configuration of QDMs. Their most recent findings were reported in an article entitled, “Configuration control of quantum dot molecules by droplet epitaxy”, published in Applied Physics Letters in 2008. “Self-assembly of semiconductor nanostructures has been intensively investigated”, Sablon explains to Nanospotlight. “In fact, the stranski-krastanow (SK)-based growth approach, which is used in lattice-mismatch systems, has made it possible to achieve a vast range of structures with control over size and density but results in a random lateral spacing of QDs which can hinder the QD functionality as a qubit in quantum computing.” Therefore, an alternative growth approach, termed droplet epitaxy (DE), was developed and integrated with the SK method. According to the researchers, this method involved the crystallization of metal droplets on the surface, forming semiconductor nanostructures. This method is an intermediate step for creating the semiconductor nano-mound templates used for subsequent QD formation. “The approach has shown previous success in the fabrication of QDPs and has been a promising method for ordering QDs locally, forming QDPs as reported in the published article titled“Self-organization of quantum-dot pairs by high-temperature droplet epitaxy” in Nanoscale Research Letters in 2006”, says Sablon.
The results demonstrated by Sablon and her colleagues are observed at a substrate temperature of 480 °C which is lower than previously reported experiments on QDMs (growth temperatures of 530 °C). “Although this temperature is lower than previous experiments, it is still categorized as high-temperature droplet epitaxy, which when compared to other droplet-related experiments that occur at about 200 °C, can result in novel nanostructures” says Sablon. “Currently, we are working towards controlling the position and size of the Ga droplets for more precise control over the position and size of QDs fabricated via this hybrid approach.”
Kimberly Annosha Sablon