Zincblende InAsxP1-x/InP Quantum Dot Nanowires for Telecom Wavelength Emission

Abstract:

Semiconductor quantum dots (QDs) are a promising platform for applications in quantum information technologies based on optics, as they enable the realization of single-photon sources (SPSs) [1]. SPSs operating in telecom bands are particularly advantageous for ultra-secure quantum optical communication via existing fiber networks, where these wavelengths minimize both loss and dispersion in telecommunication fibers. Semiconductor QDs have been proven as efficient sources in the telecom band, emitting on-demand high-purity single and indistinguishable photons, or even polarization-entangled photon pairs. Among the heterostructures explored for telecom emission, InAs_xP_1–x QDs embedded in InP nanowires (NWs) have received considerable attention. Typically, these QDs are grown along the ⟨111⟩ direction in ultrathin wurtzite (WZ) InP NWs, with a low arsenic content in the ternary alloy (x ≈ 0.25) [2]. However, NWs grown along the ⟨111⟩ direction are prone to the formation of stacking faults, which can significantly affect the QDs optical properties. To address this issue, InP  Zincblende (ZB) NWs grown along the ⟨100⟩ crystal phase offer a promising alternative, since they present a pure crystal phase across a wider range of growth conditions and diameters.

In this seminar, I will present an overview of the key technological advancements in the epitaxial growth of telecom-band-emitting quantum dots. I will present the epitaxial growth of defect-free ZB InAs_xP_1–x QDs in InP NWs along the ⟨100⟩ direction, using Au-assisted vapor-liquid-solid (VLS) growth within a Chemical Beam Epitaxy (CBE) system. I will outline the challenges involved in growing straight InP/ InAs_xP_1–x ​ heterostructure NWs across different alloy compositions. The optimized growth of InAs_xP_1–x QDs NWs with varying compositions (x = 0.24–1.00) and dimensions will be discussed, as long as the tunability of their emission as a function of QD composition and size, with an observed emission in the telecom O-band. [3]

[1] Y. Arakawa, and M. J. Holmes. Progress in Quantum-Dot Single Photon Sources for Quantum Information Technologies: A Broad Spectrum Overview. Appl. Phys. Rev., 7 (2), 021309, (2020);
[2] D. Dalacu, K. Mnaymneh, J. Lapointe, X. Wu, P. J. Poole, G. Bulgarini, V. Zwiller, and M. E. Reimer. Ultraclean Emission from InAsP Quantum Dots in Defect-Free Wurtzite InP Nanowires. Nano Lett. 12 (11), 5919– 5923,  (2012);
[3] G. Bucci, V. Zannier, F. Rossi, A. Musiał, J. Boniecki, G. Sęk, and L. Sorba. Zincblende InAsxP1-x/InP Quantum Dot Nanowires for Telecom Wavelength Emission. ACS Appl. Mater. Interfaces 16, 20, 26491–26499, (2024).

The Seminar realized in the framework of the funded projects:

• PRIN Project 20223WZ245-GROUNDS, “Growth and Optical Studies of Tunable Quantum Dots and Superlattices in Semiconductor Nanowires”
• Short Term Scientific Mission program of European COST Action OPERA (CA-20116)