Carrier lifetime of GeSn measured by spectrally resolved picosecond photoluminescence spectroscopy

Julsgaard, Brian; Driesch, Nils von den; Tidemand-Lichtenberg, Peter; Pedersen, Christian; Ikonić, Z.; Buca, D.

doi:10.1364/prj.385096

Cited by 23 publications

(24 citation statements)

References 38 publications

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“…Given the Auger coefficients estimated for GeSn in the literature [35] and the high dark recombination rates attributed to SRH and surface recombination (due to insensitivity of the measured carrier lifetimes to carrier concentrations in Refs. [41,42], we do not expect Auger recombination to play a dominant role in the 20 K to 120 K temperature range of the experimental results modeled here. In addition, QWs may further contribute to suppressing Auger recombination [36,56].…”

Section: Transport Assumptions and Modelscontrasting

confidence: 45%

“…The Nd:YAG pump laser emits 5 ns pulses at a 1064 nm center wavelength and with a small duty cycle of 8.5 × 10 −5 . The non-radiative carrier lifetime has been measured to be much shorter, in the one or few 100 ps range for GeSn layers of comparable Sn content and grown in the same CVD chamber [41,42], as discussed in more detail below. Moreover, the photon lifetime is also expected to be significantly below 100 ps, which would correspond to a high resonator quality factor of 75,000.…”

Section: Transport Assumptions and Modelsmentioning

confidence: 99%

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Modeling of a SiGeSn quantum well laser

et al. 2021

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We present comprehensive modeling of a SiGeSn multi-quantum well laser that has been previously experimentally shown to feature an order of magnitude reduction in the optical pump threshold compared to bulk lasers. We combine experimental material data obtained over the last few years with k • p theory to adapt transport, optical gain, and optical loss models to this material system (drift-diffusion, thermionic emission, gain calculations, free carrier absorption, and intervalence band absorption). Good consistency is obtained with experimental data, and the main mechanisms limiting the laser performance are discussed. In particular, modeling results indicate a low non-radiative lifetime, in the 100 ps range for the investigated material stack, and lower than expected Γ-L energy separation and/or carrier confinement to play a dominant role in the device properties. Moreover, they further indicate that this laser emits in transverse magnetic polarization at higher temperatures due to lower intervalence band absorption losses. To the best of our knowledge, this is the first comprehensive modeling of experimentally realized SiGeSn lasers, taking the wealth of experimental material data accumulated over the past years into account. The methods described in this paper pave the way to predictive modeling of new (Si)GeSn laser device concepts.

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Section: Transport Assumptions and Modelscontrasting

confidence: 45%

Section: Transport Assumptions and Modelsmentioning

confidence: 99%

Modeling of a SiGeSn quantum well laser

et al. 2021

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“…This feature has recently enabled the realization of time‐resolved upconversion spectroscopy in the 2.2–2.4 µm region with a temporal response of 75 ps. [ 19 ] The efficient translation of the MIR spectrum to the NIR is key to the success of MIRUS, since MIR detectors (e.g., HgCdTe) used in FTIR spectrometers suffer from intrinsic thermal background noise, lower detectivity, and slower response compared to their NIR counterparts. MIR noise from thermal emission of the nonlinear crystal itself is minimal due to the high transparency of the nonlinear material.…”

Section: Introductionmentioning

confidence: 99%

“…When photons are spectrally translated from MIR to NIR, the bandgap of NIR detectors is well above the energy level of room‐temperature Planck radiation, thus allowing MIRUS to operate at room temperature with low noise. Previous MIRUS implementations based on periodic‐poled lithium niobate (PPLN), [ 14,15 ] chirped‐poled lithium niobate (CPLN), [ 16,17 ] and fanout quasi‐phase‐matched lithium niobate [ 18,19 ] have covered the wavelength range (or subranges) between 2 and 5 µm. High conversion efficiency in these systems was achieved by using intracavity laser pumping scheme.…”

Section: Introductionmentioning

confidence: 99%

Room‐Temperature, High‐SNR Upconversion Spectrometer in the 6–12 µm Region

Rodrigo

Høgstedt²,

Friis³

et al. 2021

Laser & Photonics Reviews

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Mid‐infrared (MIR) spectroscopy, which has important applications in medicine, environmental monitoring, materials, and food science, is widely performed using Fourier transform infrared (FTIR) spectrometers as gold standard. Despite decades of development, FTIR systems are vulnerable to vibration and have limited temporal resolution due to reliance on mechanically scanned mirrors and MIR direct detectors that have a slower response than their near‐infrared counterparts. Using cryogenically cooled detectors, state‐of‐the‐art FTIR systems have reached a signal‐to‐noise ratio (SNR) of ≈6000 at 1 s integration time (at 4 cm−1 spectral resolution). Here, a novel MIR upconversion spectrometer (MIRUS) is presented with a record‐high SNR > 10 000 at 1 s (6 cm−1 resolution), outperforming FTIR systems by circumventing the need for sophisticated cooling and any moving part, thus enabling operation in harsh environments. It has a spectral coverage of 6–12 µm—the broadest for an upconversion spectrometer to date. The MIRUS uses broadband intracavity upconversion to convert the signal spanning the MIR fingerprint region to the near‐infrared where sensitive Si‐detector based spectrometers operate with rates easily reaching kilo spectra per second. Applications of MIRUS for gas sensing, plastic identification, and rapid photopolymerization monitoring are demonstrated.

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“…Time-resolved methods applied to a vast range of experimental techniques, for example, absorption and photoluminescence (PL) spectroscopies are a primer to study the kinetics of the carriers. Although successful in addressing the spin physics of Ge 0.95 Sn 0.05 [19], time-resolved measurements has seldom been applied to Ge 1−x Sn x alloys owing to the narrow band gap [20]. In addition to nontrivial structural problems associated with the spontaneous segregation of Sn, the band gap of Ge 1−x Sn x typically lies in the shortwave or mid-infrared region.…”

Section: Introductionmentioning

confidence: 99%

Continuous-Wave Magneto-Optical Determination of the Carrier Lifetime in Coherent Ge1−xSnx/Ge Heterostructures

et al. 2020

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We present a magneto-optical study of the carrier dynamics in compressively strained Ge 1−x Sn x films with Sn content up to 10% epitaxially grown on Ge on Si(001) virtual substrates. We leverage the Hanle effect under steady-state excitation to study the spin-dependent optical transitions in the presence of an external magnetic field. This allows us to obtain direct access to the dynamics of the optically induced carrier population. Our approach reveals that at cryogenic temperatures the effective lifetime of the photogenerated carriers in coherent Ge 1−x Sn x is on the subnanosecond timescale. Supported by a model estimate of the radiative lifetime, our measurements indicate that carrier recombination is dominated by nonradiative processes. Our results thus provide central information to improve the fundamental understanding of carrier kinetics in this advanced direct-band-gap group-IV-material system. Such knowledge can be a stepping stone in the quest for the implementation of Ge 1−x Sn x -based functional devices.

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Carrier lifetime of GeSn measured by spectrally resolved picosecond photoluminescence spectroscopy

Abstract: This is a repository copy of Carrier lifetime of GeSn measured by spectrally resolved picosecond photoluminescence spectroscopy.

Cited by 23 publications

References 38 publications

Modeling of a SiGeSn quantum well laser

Modeling of a SiGeSn quantum well laser

Room‐Temperature, High‐SNR Upconversion Spectrometer in the 6–12 µm Region

Continuous-Wave Magneto-Optical Determination of the Carrier Lifetime in Coherent Ge1−xSnx/Ge Heterostructures

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