Abstract
The performance of infrared photodetectors based on submonolayer quantum dots was investigated as a function of the arsenic flux. All the devices showed similar figures of merit and a very high specific detectivity above 1 × 1011 cm Hz1/2/W at 12 K, despite the fact that cross-sectional scanning tunneling microscopy images pointed out a strong reduction in the density of such nanostructures with decreasing arsenic flux. This contrast is a consequence of the small size and low In content of the submonolayer quantum dots that lead to a strong delocalization of the electrons wave function and, therefore, reduce the advantage of samples having a very high density of quantum dots. A simple strain model showed that the properties of these nanostructures are limited by the lack of vertical alignment of the small two-dimensional InAs islands resulting from the strong segregation of In atoms. We have proposed some ways to improve the growth of submonolayer quantum dots and believe that, after further optimization, such nanostructures might provide devices with superior performance.
Original language | English |
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Article number | 113357 |
Number of pages | 8 |
Journal | Sensors and Actuators, A: Physical |
Volume | 334 |
DOIs | |
Publication status | Published - 1 Feb 2022 |
Funding
Kevin Vallejo is a Ph.D. student at Boise State University scheduled to graduate in the Fall of 2021. He obtained a Bachelor of Science degree from The University of Texas at El Paso in 2016, and a Master´s degree in Engineering from Boise State University in 2020. During the Spring 2015 semester, Kevin received the US Department of State Benjamin A. Gilman scholarship to study at Åbo Akademi University in Finland. In 2019, he received the US National Nuclear Science Foundation Graduate Fellowship, the US Intelligence Community Postdoctoral Fellowship, and Dean's Scholar award from Boise State University for outstanding scholarship. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil ( CAPES ) - Finance Code 001 , by CNPq (grant 311687/2017-2 ), and by European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie project 4PHOTON grant agreement No 721394 .
Funders | Funder number |
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Boise State University | |
European Union's Horizon 2020 - Research and Innovation Framework Programme | |
Marie Skłodowska‐Curie | 721394 |
Keywords
- InAs
- Infrared photodetector
- Molecular beam epitaxy
- Scanning tunneling microscopy
- Segregation
- Submonolayer quantum dots