Extended-SWIR Photodetection in All-Group IV Core/Shell Nanowires

Luo, Lu; Assali, Simone; Atalla, Mahmoud R. M.; Koelling, Sebastian; Attiaoui, Anis; Daligou, Gérard; Martí, Sara; Arbiol, Jordi; Moutanabbir, Oussama

doi:10.1021/acsphotonics.1c01728

Cited by 14 publications

(12 citation statements)

References 51 publications

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“…1b. The typical sunburst-like morphology of the Ge 0.90 Sn 0.10 shell, with Sn-rich {112} wide facets and Ge-rich {110} narrow facets 19,26 , is preserved across the entire 250 nm thickness of the shell. The composition of the GeSn shell was characterized using APT measurements, as displayed in Fig.…”

Section: Nanowires Growth and Characterizationmentioning

confidence: 99%

Strong extended SWIR cavity resonances in a single GeSn nanowire

Kim

Assali

Joo

et al. 2022

Preprint

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Nanowires are promising platforms for realizing ultra-compact light sources for photonic integrated circuits. In contrast to impressive progress on light confinement and stimulated emission in III-V and II-VI semiconductor nanowires, there has been no experimental demonstration showing the potential to achieve strong cavity effects in a bottom-up grown single group-IV nanowire, which is a prerequisite for realizing silicon-compatible infrared nanolasers. Herein, we address this limitation and present the first experimental observation of cavity-enhanced strong photoluminescence from a single Ge/GeSn core/shell nanowire. A sufficiently large Sn content (~ 10 at%) in the GeSn shell leads to a direct bandgap gain medium, allowing a strong reduction in a material loss upon optical pumping. Efficient optical confinement in a single nanowire enables many round trips of emitted photons between two facets of a nanowire, achieving a narrow width of 3.3 nm. Our demonstration opens new possibilities for ultrasmall on-chip light sources towards realizing photonic-integrated circuits in the underexplored range of extended SWIR.

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Section: Nanowires Growth and Characterizationmentioning

confidence: 99%

Strong extended SWIR cavity resonances in a single GeSn nanowire

Kim

Assali

Joo

et al. 2022

Preprint

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“…However, the control of NW orientation, size and distribution face challenge. Choosing Au [ 27 ] or AuAg [ 28 ] as catalyst, controllable GeSn homogeneous [ 29 ] and Ge/GeSn core/shell [ 24 , 30 ] NWs were prepared by chemical vapor deposition. Yet, the use of noble metals may degrade the optical performance of GeSn through inducing deep energy levels in the bandgap of GeSn, similar to the cases in Ge [ 31 ].…”

Section: Introductionmentioning

confidence: 99%

Scalable fabrication of self-assembled GeSn vertical nanowires for nanophotonic applications

Lin

Ding

et al. 2023

Nanophotonics

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In this work, scalable fabrication of self-assembled GeSn vertical nanowires (NWs) based on rapid thermal annealing (RTA) and inductively coupled-plasma (ICP) dry etching was proposed. After thermal treatment of molecular-beam-epitaxy-grown GeSn, self-assembled Sn nanodots (NDs) were formed on surface and the spontaneous emission from GeSn direct band was enhanced by ∼5-fold. Employing the self-assembled Sn NDs as template, vertical GeSn NWs with a diameter of 25 ± 6 nm and a density of 2.8 × 109 cm−2 were obtained by Cl-based ICP dry etching technique. A prototype GeSn NW photodetector (PD) with rapid switching ability was demonstrated and the optoelectronic performance of Ge NW PD was systematically studied. The GeSn NW PD exhibited an ultralow dark current density of ∼33 nA/cm2 with a responsivity of 0.245 A/W and a high specific detectivity of 2.40 × 1012 cm Hz1/2 W−1 at 1550 nm under −1 V at 77 K. The results prove that this method is prospective for low-cost and scalable fabrication of GeSn NWs, which are promising for near infrared or short wavelength infrared nanophotonic devices.

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“…Ge 1−x Sn x alloys constitute an emerging class of group IV semiconductors providing a tunable narrow bandgap, which has been highly attractive to implement scalable, silicon-compatible mid-infrared photonic and optoelectronic devices [1]. This potential becomes increasingly significant with the recent progress in nonequilibrium growth processes enabling high Sn content Ge 1−x Sn x layers and heterostructures leading to the demonstration of a variety of monolithic mid-infrared emitters and detectors [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Notwithstanding the recent developments in device engineering, the impact of structural characteristics on the basic behavior of charge carriers is yet to be fully understood.…”

Section: Introductionmentioning

confidence: 99%

Radiative Carrier Lifetime in Ge$_{1-x}$Sn$_x$ Mid-Infrared Emitters

Daligou¹,

Attiaoui²,

Assali³

et al. 2023

Preprint

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Ge1−xSnx semiconductors hold the premise for large-scale, monolithic mid-infrared photonics and optoelectronics. However, despite the successful demonstration of several Ge1−xSnx-based photodetectors and emitters, key fundamental properties of this material system are yet to be fully explored and understood. In particular, little is known about the role of the material properties in controlling the recombination mechanisms and their consequences on the carrier lifetime. Evaluating the latter is in fact fraught with large uncertainties that are exacerbated by the difficulty to investigate narrow bandgap semiconductors. To alleviate these limitations, herein we demonstrate that the radiative carrier lifetime can be obtained from straightforward excitation power-and temperaturedependent photoluminescence measurements. To this end, a theoretical framework is introduced to simulate the measured spectra by combining the band structure calculations from the k.p theory and the envelope function approximation (EFA) to estimate the absorption and spontaneous emission. The model computes explicitly the momentum matrix element to estimate the strength of the optical transitions in single bulk materials, unlike the joint density of states (JDOS) model which assumes a constant matrix element. Based on this model, the temperature-dependent emission from Ge0.83Sn0.17 samples at a biaxial compressive strain of −1.3% was investigated. The simulated spectra reproduce accurately the measured data thereby enabling the evaluation of the steady-state radiative carrier lifetimes, which are found in the 3-22 ns range for temperatures between 10 and 300 K at an excitation power of 0.9 kW/cm 2 . For a lower power of 0.07 kW/cm 2 , the obtained lifetime has a value of 1.9 ns at 4 K. The demonstrated approach yielding the radiative lifetime from simple emission spectra will provide valuable inputs to improve the design and modeling of Ge1−xSnx-based devices.

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Extended-SWIR Photodetection in All-Group IV Core/Shell Nanowires

Cited by 14 publications

References 51 publications

Strong extended SWIR cavity resonances in a single GeSn nanowire

Strong extended SWIR cavity resonances in a single GeSn nanowire

Scalable fabrication of self-assembled GeSn vertical nanowires for nanophotonic applications

Radiative Carrier Lifetime in Ge$_{1-x}$Sn$_x$ Mid-Infrared Emitters

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