Graphical Abstract

The room-temperature light emission of uncapped Ⅲ-Ⅴ semiconductor quantum dots is used to investigate the properties and evolution of the surface under exposure to a humid environment. Enhanced photoluminescence intensity resulting from exposure to polar molecules has already been reported; here we demonstrate that the external environment also has a relevant effect on the emission energy of quantum dots. Experimental results are interpreted on the basis of a model of the quantum system that takes into account the formation of oxide on pristine Ⅲ-Ⅴ surfaces and the presence of surface states. As a result of our study, we can clearly distinguish the effect of surface oxidation from that of surface state passivation on the emission of InAs surface quantum dots. This work sheds new light on the properties of semiconductor surface quantum dots as building blocks of novel and highly efficient sensing devices based on optical transduction.
Wu, J.; Chen, S. M.; Seeds, A.; Liu, H. Y. Quantum dot optoelectronic devices: Lasers, photodetectors and solar cells. J. Phys. D: Appl. Phys. 2015, 48, 363001.
Lodahl, P.; Mahmoodian, S.; Stobbe, S. Interfacing single photons and single quantum dots with photonic nanostructures. Rev. Mod. Phys. 2015, 87, 347-400.
Milla, M. J.; Ulloa, J. M.; Guzmán, Á. Strong influence of the humidity on the electrical properties of InGaAs surface quantum dots. ACS Appl. Mater. Interfaces 2014, 6, 6191-6195.
Lin, A.; Liang, B. L.; Dorogan, V. G.; Mazur, Y. I.; Tarasov, G. G.; Salamo, G. J.; Huffaker, D. L. Strong passivation effects on the properties of an InAs surface quantum dot hybrid structure. Nanotechnology 2013, 24, 075701.
Milla, M. J.; Ulloa, J. M.; Guzmán, Á. High optical sensitivity to ambient conditions of uncapped InGaAs surface quantum dots. Appl. Phys. Lett. 2012, 100, 131601.
Milla, M. J.; Ulloa, J. M.; Guzmán, Á. Dependence of surface InGaAs quantum dot luminescence on the molecular properties of the environment. Appl. Phys. Express 2013, 6, 092002.
De Angelis, R.; Casalboni, M.; Hatami, F.; Ugur, A.; Masselink, W. T.; Prosposito, P. Vapour sensing properties of InP quantum dot luminescence. Sensor. Actuat. B-Chem. 2012, 162, 149-152.
Hestroffer, K.; Braun, R.; Ugur, A.; Tomm, J. W.; Hackbarth, S.; Röder, B.; Hatami, F. Surface InP/In0.48Ga0.52P quantum dots: Carrier recombination dynamics and their interaction with fluorescent dyes. J. Appl. Phys. 2013, 114, 163510.
Chen, M. X.; Kobashi, K.; Chen, B.; Lu, M.; Tour, J. M. Functionalized self-assembled InAs/GaAs quantum-dot structures hybridized with organic molecules. Adv. Funct. Mater. 2010, 20, 469-475.
Seker, F.; Meeker, K.; Kuech, T. F.; Ellis, A. B. Surface chemistry of prototypical bulk Ⅱ-Ⅵ and Ⅲ-Ⅴ semiconductors and implications for chemical sensing. Chem. Rev. 2000, 100, 2505-2536.
Frigeri, P.; Seravalli, L.; Trevisi, G.; Franchi, S. Molecular beam epitaxy: An overview. In Reference Module in Materials Science and Materials Engineering; Hashmi, S., Ed.; Elsevier: Oxford, 2016.
Bernstein, R. W.; Borg, A.; Husby, H.; Fimland, B. O.; Grepstad, J. K. Capping and decapping of MBE grown GaAs(001), Al0.5Ga0.5As(001), and AlAs(001) investigated with ASP, PES, LEED, and RHEED. Appl. Surf. Sci. 1992, 56-58, 74-80.
Auf der Maur, M.; Penazzi, G.; Romano, G.; Sacconi, F.; Pecchia, A.; Di Carlo, A. The multiscale paradigm in electronic device simulation. IEEE T. Electron Dev. 2011, 58, 1425-1432.
Barettin, D.; de Angelis, R.; Prosposito, P.; Auf der Maur, M.; Casalboni, M.; Pecchia, A. Model of a realistic InP surface quantum dot extrapolated from atomic force microscopy results. Nanotechnology 2014, 25, 195201.
Sacconi, F.; Auf der Maur, M.; Di Carlo, A. Optoelectronic properties of nanocolumn InGaN/GaN LEDs. IEEE T. Electron Dev. 2012, 59, 2979-2987.
Seravalli, L.; Bocchi, C.; Trevisi, G.; Frigeri, P. Properties of wetting layer states in low density InAs quantum dot nanostructures emitting at 1.3 µm: Effects of InGaAs capping. J. Appl. Phys. 2010, 108, 114313.
Seravalli, L.; Gioannini, M.; Cappelluti, F.; Sacconi, F.; Trevisi, G.; Frigeri, P. Broadband light sources based on InAs/InGaAs metamorphic quantum dots. J. Appl. Phys. 2016, 119, 143102.
Seravalli, L.; Trevisi, G.; Frigeri, P. Calculation of metamorphic two-dimensional quantum energy system: Application to wetting layer states in InAs/InGaAs metamorphic quantum dot nanostructures. J. Appl. Phys. 2013, 114, 184309.
Smaali, K.; El Hdiy, A.; Molinari, M.; Troyon, M. Band-gap determination of the native oxide capping quantum dots by use of different kinds of conductive AFM probes: Example of InAs/GaAs quantum dots. IEEE T. Electron Dev. 2010, 57, 1455-1459.
Bierwagen, O. Indium oxide—A transparent, wide-band gap semiconductor for (opto)electronic applications. J. Phys. D: Appl. Phys. 2015, 30, 024001.
Nakkar, A.; Folliot, H.; Le Corre, A.; Doré, F.; Alghoraibi, I.; Labbé, C.; Elias, G.; Loualiche, S.; Pistol, M. E.; Caroff, P. et al. Optical properties and morphology of InAs/InP (113)B surface quantum dots. Appl. Phys. Lett. 2008, 92, 231911.
Saito, T.; Schulman, J. N.; Arakawa, Y. Strain-energy distribution and electronic structure of InAs pyramidal quantum dots with uncovered surfaces: Tight-binding analysis. Phys. Rev. B 1998, 57, 13016-13019.
Walther, C.; Blum, R. P.; Niehus, H.; Masselink, W. T.; Thamm, A. Modification of the Fermi-level pinning of GaAs surfaces through InAs quantum dots. Phys. Rev. B 1999, 60, R13962-R13965.
Halpern, E.; Cohen, G.; Gross, S.; Henning, A.; Matok, M.; Kretinin, A. V.; Shtrikman, H.; Rosenwaks, Y. Measuring surface state density and energy distribution in InAs nanowires. Phys. Status Solidi A 2014, 211, 473-482.
De Angelis, R.; D'Amico, L.; Casalboni, M.; Hatami, F.; Masselink, W. T.; Prosposito, P. Photoluminescence sensitivity to methanol vapours of surface InP quantum dot: Effect of dot size and coverage. Sensor. Actuat. B-Chem. 2013, 189, 113-117.
Zhang, X. Q.; Ptasinska, S. Dissociative adsorption of water on an H2O/GaAs(100) interface: In situ near-ambient pressure XPS studies. J Phys Chem C 2014, 118, 4259-4266.
Losurdo, M.; Wu, P. C.; Kim, T. -H.; Bruno, G.; Brown, A. S. Cysteamine-based functionalization of InAs surfaces: Revealing the critical role of oxide interactions in biasing attachment. Langmuir 2012, 28, 1235-1245.
Shiramine, K. -I.; Muto, S.; Shibayama, T.; Sakaguchi, N.; Ichinose, H.; Kozaki, T.; Sato, S.; Nakata, Y.; Yokoyama, N.; Taniwaki, M. Tip artifact in atomic force microscopy observations of InAs quantum dots grown in Stranski-Krastanow mode. Appl. Phys. Lett. 2007, 101, 033527.