Abstract:We report the characteristics of the strained In 0.65 Ga 0.35 As triple quantum well (QW) diode lasers grown by metalorganic vapor phase epitaxy (MOVPE) on lattice-mismatched substrates such as GaAs or Si, by utilizing InP metamorphic buffer layers (MBLs) in conjunction with InAs nanostructure-based dislocation filters. As the lattice-mismatch between the substrate and InP MBL increases, higher threshold current densities and lower slope efficiencies were observed, together with higher temperature sensitivitie… Show more
“… Fig. 7 The historical evolution of 1.55-μm band lasers monolithically integrated on Si by direct epitaxial growth in terms of threshold current density reduction and increase in maximum lasing temperature 14 , 15 , 18 , 19 , 21 , 22 , 42 , 45 – 48 …”
A reliable, efficient and electrically-pumped Si-based laser is considered as the main challenge to achieve the integration of all key building blocks with silicon photonics. Despite the impressive advances that have been made in developing 1.3-μm Si-based quantum dot (QD) lasers, extending the wavelength window to the widely used 1.55-μm telecommunication region remains difficult. In this study, we develop a novel photonic integration method of epitaxial growth of III-V on a wafer-scale InP-on-Si (100) (InPOS) heterogeneous substrate fabricated by the ion-cutting technique to realize integrated lasers on Si substrate. This ion-cutting plus epitaxial growth approach decouples the correlated root causes of many detrimental dislocations during heteroepitaxial growth, namely lattice and domain mismatches. Using this approach, we achieved state-of-the-art performance of the electrically-pumped, continuous-wave (CW) 1.55-µm Si-based laser with a room-temperature threshold current density of 0.65 kA/cm−2, and output power exceeding 155 mW per facet without facet coating in CW mode. CW lasing at 120 °C and pulsed lasing at over 130 °C were achieved. This generic approach is also applied to other material systems to provide better performance and more functionalities for photonics and microelectronics.
“… Fig. 7 The historical evolution of 1.55-μm band lasers monolithically integrated on Si by direct epitaxial growth in terms of threshold current density reduction and increase in maximum lasing temperature 14 , 15 , 18 , 19 , 21 , 22 , 42 , 45 – 48 …”
A reliable, efficient and electrically-pumped Si-based laser is considered as the main challenge to achieve the integration of all key building blocks with silicon photonics. Despite the impressive advances that have been made in developing 1.3-μm Si-based quantum dot (QD) lasers, extending the wavelength window to the widely used 1.55-μm telecommunication region remains difficult. In this study, we develop a novel photonic integration method of epitaxial growth of III-V on a wafer-scale InP-on-Si (100) (InPOS) heterogeneous substrate fabricated by the ion-cutting technique to realize integrated lasers on Si substrate. This ion-cutting plus epitaxial growth approach decouples the correlated root causes of many detrimental dislocations during heteroepitaxial growth, namely lattice and domain mismatches. Using this approach, we achieved state-of-the-art performance of the electrically-pumped, continuous-wave (CW) 1.55-µm Si-based laser with a room-temperature threshold current density of 0.65 kA/cm−2, and output power exceeding 155 mW per facet without facet coating in CW mode. CW lasing at 120 °C and pulsed lasing at over 130 °C were achieved. This generic approach is also applied to other material systems to provide better performance and more functionalities for photonics and microelectronics.
“…Some other notable progress includes wavelength shifting of GaSb‐based strained QWs to the telecom band, [ 14–16 ] and modulating Ge bulk crystals toward “quasi‐direct bandgap” emission. [ 17,18 ] Yet, integrating InP on Si is still advantageous, [ 19 ] so as to exploit the mature InP technologies for integration into SiPh. As shown in Table 1, only by minimizing defect density in the InP buffer can subsequent lasers operate efficiently.…”
Room‐temperature continuous wave (RT‐CW) electrically pumped 1550 nm indium phosphide (InP)‐based laser diodes are realized on complementary metal‐oxide‐semiconductor (CMOS) compatible silicon (Si) substrates by direct heteroepitaxy. Dynamic properties are investigated by gain switching and small signal modulation measurements. A maximum 3 dB bandwidth of 5.3 GHz is demonstrated, along with a narrow optical pulse with a width of 1.5 ns. The dark current density of 490 mA cm−2 at −1 V bias is an order of magnitude higher than identical devices grown and fabricated on native InP substrates. Also, reliability measurements and failure analysis are carried out for the lasers on Si. The lasers operate stably over 200 hours (h) at 10 °C under CW operation without apparent change in threshold or output power. In sharp contrast, a rapid failure occurs at 60 °C under pulsed operation following 5.6 h of aging. To further improve device characteristics for lasers on Si, the dislocation density of the InP template is reduced by introducing a 2 μm‐thick compositionally graded In0.4Ga0.6 As buffer. The resulting surface defect density is as low as 4.5 × 107 cm−2, which is expected to improve the performance and reliability of long wavelength lasers grown directly on Si.
“…Metamorphic buffer layers generally alter the material lattice constant by grading an alloy composition toward the desired lattice constant using one of several common transitions, including linear grading, step grading, or logarithmic grading [5]. Strained superlattices have been previously used as a means to filter defects to reduce threading dislocation density (TDD), as well as reducing surface roughness through mitigation of local lateral strain fluctuations [6][7][8][9]. In this work, metamorphic strained superlattices are implemented as both a composition-shifting metamorphic buffer and a defect filter [10].…”
Three types of GaAsP metamorphic buffer layers, including linearly graded, step graded, and metamorphic superlattices, were compared for the purposes of virtual substrates for red laser diode heterostructures. Laser diodes were fabricated on GaAs substrates and relaxed GaAsP metamorphic superlattice virtual substrates. A laser diode structure with a tensile-strained quantum well on a standard miscut GaAs substrate achieved TM-polarized emission at a 638 nm wavelength with 45% peak power conversion efficiency (PCE) at a 880 mW continuous wave (CW) output power with T0 = 77 K and T1 = 266 K. An analogous laser diode structure with a compressively strained quantum well on the metamorphic superlattice emitted TE-polarized 639 nm light with 35.5% peak PCE at 880 mW CW with T0 = 90 K and T1 = 300 K.
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