Influence of auger recombination on the temperature sensitivity of bulk and strained quantum well 1.3-μm semiconductor lasers
01 May 1996-Vol. 2693, pp 592-599
TL;DR: In this article, a combined theoretical and experimental analysis was performed to identify the dominant factors contributing to the poor temperature sensitivity of semiconductor laser, and it was shown that radiative recombination is not the dominant mechanism of the laser temperature sensitivity.
Abstract: The temperature sensitivity of the threshold current of 1.3 micrometer semiconductor lasers, denoted by the characteristic temperature T0, has remained low, with values ranging from 40 K up to a maximum of order 100 K. We report here on a combined theoretical and experimental analysis to identify the dominant factors contributing to this poor temperature sensitivity. We have determined directly the temperature dependence of the radiative current density, Jrad, by measuring the integrated spontaneous emission, L, from bulk and strained quantum well buried heterostructure devices. We find an effective T0 for Jrad of around 200 K for the bulk device and around 300 K for the quantum well device, in good agrement with the theoretical prediction for ideal lasers. This radiative temperature dependence compares with the measured T0 of around 50 - 60 K for the total threshold current density in both devices, from which we conclude that radiative recombination is not the dominant mechanism of the temperature sensitivity of the laser. We also find from the spontaneous emission data that just below threshold L varies with current I as I varies direct as L3/2, which is expected in the Boltzmann approximation if auger recombination is the dominant current path. We have used these findings to estimate T0 from as simple analytic expression we have derived and find values at room temperature of 40 - 100 K, in agreement with experiment. This poor T0 results both from the temperature dependence of the differential gain and by the major contribution of auger recombination to the total threshold current.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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TL;DR: In this paper, the authors calculated the bandgap dependence of the main Auger processes and concluded that the dominant Auger process over this wavelength range could either be the phonon-assisted CHCC process or the band-to-band CHSH process.
Abstract: The variation of the threshold current of an unstrained 1.48-/spl mu/m InGaAsP quantum-well (QW) laser has been measured as a function of hydrostatic pressure up to 27 kbar. We combine this result with theoretical calculations to extract the bandgap dependence of the Auger coefficient, C, over a range of 200 meV. We find that over this range C reduces by a factor of about three. We have calculated the bandgap dependence of the main Auger processes and conclude that the dominant Auger process over this wavelength range could either be the phonon-assisted CHCC process or the band-to-band CHSH process. Based on this result, we have estimated the threshold current density of strained and unstrained lasers with wavelengths ranging from 1.75 to 1.3 /spl mu/m using both these processes. We get good agreement between theory and experiment in both cases and show that Auger recombination is the dominant current contribution in 1.5- and 1.3-/spl mu/m devices.
38 citations
35 citations
TL;DR: In this paper, the temperature dependence of the characteristic temperature T/sub 0/ of semiconductor quantum-well lasers is investigated using detailed simulations, and it is shown that, with inclusion of the continuum state filling and interband mixing, the most important features experimentally observed in the temperature depend on the optical gain and the nonradiative recombination processes.
Abstract: The temperature dependence of the characteristic temperature T/sub 0/ of semiconductor quantum-well lasers is investigated using detailed simulations. The critical-temperature-dependent processes are the optical gain and the nonradiative recombination. The gain model is based on k /spl middot/ p theory with the multiple quantum wells in the active layer represented by a superlattice. The Auger process is assumed to be thermally activated. It is shown that, with inclusion of the continuum state filling and interband mixing, the most important features experimentally observed in the temperature dependence of the T/sub 0/ value can be explained. The continuum state filling and band nonparabolicity cause a significant deviation from the ideal linear carrier density versus temperature relation for quantum wells. The results are compared to experiment for broad area devices lasing at 980 nm and 1.3, and 1.55 /spl mu/m, and show good agreement over a broad range of temperature.
16 citations
28 Jun 2019
TL;DR: In this article, a combination of temperature and hydrostatic pressure techniques was used to identify the dominant cause for the performance degradation of type-I mid-infrared laser with increasing wavelength and temperature.
Abstract: The advances in semiconductor technology coupled with the potential of lab-on-chip spectroscopy, long wavelength telecommunications and small-scale optical interconnects has invigorated academic and commercial interest in mid-infrared optoelectronics. However, significant challenges remain. This thesis explores two approaches for mid-infrared optoelectronic lasers.
Type-I GaSb quantum well lasers exhibit some of the highest performance metrics of any semiconductor laser system in the 2 μm – 3 μm wavelength range. However, the threshold current density increases substantially with increasing wavelength and temperature, impacting component reliability and the overall efficiency of a laser-based optoelectronic system.
Through a combination of temperature and hydrostatic pressure techniques, Auger recombination is identified as the dominant cause for the performance degradation of type-I mid-infrared laser with increasing wavelength and temperature. Using hydrostatic pressure measurements, the wavelength dependence of the Auger coefficient over the 2 μm - 3 μm range is constructed, revealing two important regimes. At wavelengths 2 μm, the CHSH process is effectively suppressed due to the energetic separation between the lasing energy and the spin-orbit split-off band. In this regime another Auger process, such as CHCC or CHLH recombination begins to dominate, increasing exponentially with wavelength. The temperature dependence of the radiative and non-radiative threshold current density indicates that this Auger process has an activated character and is sensitive to the intrinsic properties of the quantum well band structure.
To leverage the advanced manufacturing capabilities and high yields of the Si-microelectronics industry, there is intense research activity to realise CMOS compatible optoelectronics. One emerging strategy is to augment the optical properties of group-IV materials through band structure engineering, such as incorporating Sn into the Ge lattice.
Hydrostatic pressure measurements of the GeSn absorption edge exhibit an intermediate pressure coefficient between that of the Γ and L conduction band critical points. This is indicative of strong band mixing effects in the GeSn alloy. In the presence of band mixing the conventional distinction between the indirect and direct band gap breaks down. Instead it is more appropriate to discuss the nature of the band gap in terms of the fractional Γ-character of the conduction band states at the band edge. The pressure coefficient of the absorption edge for samples with Sn content between 6% – 10% reveal a continuous evolution in the Γ-character with increasing Sn-concentration. High Γ-character is observed even at low Sn concentrations of 6%, when the GeSn alloy is expected to exhibit a fundamentally indirect band gap. These band mixing effects have important implications for designing efficient photonic and electronic devices utilizing GeSn and related material systems.
9 citations
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...We should also note here that in several publications the measured room temperature T0 values for the radiative current is close to that predicted by T0 = T [299], [303], [333]–[336]....
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TL;DR: In this paper , the authors investigated the dominant Auger mechanism in mid-infrared emitting quantum wells by characterizing a range of type-I InGaAsSb quantum well lasers operating within the 2 - 3 μm wavelength range.
Abstract: Auger recombination is known to be a significant non-radiative process limiting near- and mid-infrared quantum well lasers. The one-dimensional confinement of quantum wells and small band offsets (relative to the bandgap) permits two fundamentally different categories of Auger mechanisms to operate. These mechanisms may be identified as either activated or thresholdless in nature. In this work, we investigate the nature of the dominant Auger mechanism in mid-infrared emitting quantum wells by characterizing a range of type-I InGaAsSb quantum well lasers operating within the 2 - 3 μm wavelength range. The temperature dependence of both the threshold current density and integrated spontaneous emission reveal that the threshold current is dominated by radiative recombination up to a break-point temperature (occurring below 200 K). Beyond the break point temperature, the exponential dependence of the threshold current increases rapidly. The deterioration in the stability of lasing threshold indicates that a thermally activated Auger process is dominant in all devices and is sensitive to the population of heavy-holes in the quantum wells.
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TL;DR: In this paper, the temperature dependence of the differential quantum efficiency ηd and threshold current density Jth of 1.6 µm In1-xGaxAsyP1y lasers is investigated.
Abstract: Measurements are presented of the temperature dependence of the differential quantum efficiency ηd and threshold current density Jth of 1.6 µm In1-xGaxAsyP1-y lasers. The observed sharp decrease in ηd near room temperature is interpreted as due to absorption associated with transitions of electrons from the split-off valence band into holes injected into and thermally generated within the heavy hole valence band. Preliminary calculations using conventional laser theory predict a temperature variation corresponding to T0145 K. This together with the influence of ηd, appears to be sufficient to explain most of the observed temperature variation of Jth.
210 citations
TL;DR: In this article, the authors reported the determination of Auger recombination coefficients in bulk and quantum well InGaAs by time-resolved luminescence measurements, and they found that the Auger coefficient decreases slightly with decreasing well width.
Abstract: We report the determination of Auger recombination coefficients in bulk and quantum well InGaAs by time‐resolved luminescence measurements. In bulk InGaAs the coefficient is C=3.2×10−28 cm6/s and has the temperature dependence of the valence‐band Auger effect involving the split‐off valence band. In 11 nm quantum well InGaAs we find C=0.9×10−28 cm6/s, independent of temperature. The Auger coefficient decreases slightly with decreasing well width.
123 citations
TL;DR: In this article, the temperature dependence of long wavelength (1.5 μm) quantum-well lasers has been studied theoretically assuming that the dominant contribution to the threshold current is from phonon-assisted Auger recombination.
Abstract: The temperature dependence of long wavelength (1.5 μm) quantum‐well lasers has been studied theoretically assuming that the dominant contribution to the threshold current is from phonon‐assisted Auger recombination. It is found that the best possible value of T0 at room temperature is ≊100 K. Gain calculations based on the InGaAs/InGaAsP/InP system operating at 1.5 μm indicate that the main cause of the reduction from this ideal value is due to the temperature dependence of the threshold carrier density. We also comment on the implication of this for the high temperature operation of tensile and compressive lasers.
85 citations
TL;DR: In this paper, the theoretical and experimental results for the temperature dependence of amplified spontaneous emission (ASE) in laser diodes and light-emitting Diodes (LEDs) are presented, taking into account conduction band nonparabolicity and band-gap renormalization.
Abstract: Theoretical and experimental results for the temperature dependence of amplified spontaneous emission (ASE) in laser diodes (LDs) and light-emitting diodes (LEDs) are presented. The theoretical model takes into account conduction band nonparabolicity and band-gap renormalization. The gain spectrum is calculated from the theoretical spontaneous emission spectrum, and both compare very well with experimental data. From a fit to the observed temperature dependence of ASE for an LED and the gain spectrum for an LD with a structure identical to that of the LED except for mirror reflectivity, it is possible to establish carrier density as a function of injection current for both devices. It is shown that photons fluctuating into cavity modes give rise to substantial subthreshold carrier pinning in laser diodes. These fluctuations extract an extra current from the device and play an increasingly important role with increasing temperature. >
64 citations
TL;DR: In this article, the electron leakage through the heterobarrier consisting of a thin InGaAsP active layer and a pInP confining layer was directly observed by using a novel double heterostructure (DH) structure.
Abstract: The electron leakage through the heterobarrier consisting of a thin InGaAsP active layer and a p‐InP confining layer was directly observed by using a novel InGaAsP/InP light‐emitting diode (LED) structure. In the present structure, electrons leaking from the active layer were confined in a subsidiary quaternary layer having a crystal composition different from that of the active layer, and the recombination emission caused by these electrons was optically detected. Experimental results showed that significant electron leakage can occur in the present InGaAsP/InP double heterostructure (DH) system, suggesting a possibility of the electron leakage being one of the dominant mechanisms of sublinearity in the light intensity‐current characteristics in InGaAsP/InP DH LED’s operating at wavelengths shorter than 1.3 μm and also of the temperature dependence of threshold current in laser diodes.
54 citations