Demonstration of high-speed staggered lineup GaAsSb-InP unitraveling carrier photodiodes

Type-II GaInAsSb/InP Uniform Absorber High Speed Uni-Traveling Carrier Photodiodes

“…(1) for the GaInAsSb absorber indicates an f 3dB = 240 GHz (τ 3dB = 0.66 ps) for a 13 µm 2 area despite a 16% thicker absorber layer, suggesting that diffusive electron transport in our GaInAsSb absorber indeed is competitive with that of GaInAs. Because the present InP collector is nearly of the same thickness as that of [17], by accounting for a collector delay τ C = 0.26 ps [6,10] Assuming responsivity scales with absorber layer thickness and mobility [6] (recalling the effective absorber length in [17] is 172 nm for two-passes through the 86 nm GaInAs layer), yields μ Q /µ GaInAs = (94•172)/(126•100) = 1.28, which is consistent with the value extracted from bandwidth comparison (with an ~11% discrepancy that is likely associated to a higher recombination rate due to the 6.5× higher doping level in our GaInAsSb absorber with respect to that of [17]). The bandgap calculation for the ternary and quaternary III-V alloys depends on both the selected interpolation scheme and the bowing parameters.…”

“…In light of these considerations, some of us [6] demonstrated UTC-PDs using a GaAsSb absorber in 2005, exploiting the fact that the conduction band edge of GaAs 0.51 Sb 0.49 is higher than that of InP ("Type-II" alignment), favoring electron transport even under flat-band conditions. The operating principle of a Type-II UTC-PD was successfully demonstrated but with lower bandwidths than possible with a GaInAs absorber of the same thickness because of a lower electron mobility (diffusivity) in the GaAs 0.51 Sb 0.49 alloy in comparison to Ga 0.47 In 0.53 As [6,7]. This imposes a serious limitation on the overall performance of Type-II UTC-PDs in terms of the trade-off between PD responsivity (scaling with ~W A ) and the absorber diffusion delay (scaling with ~W A 2 ).…”

Characteristics of strained GaAs1−ySby (0.16 ≤ y ≤ 0.69) quantum wells on InP substrates

“…Ternary GaAsSb alloys on InP substrates have applications in many advanced microelectronic and optoelectronic devices, such as high-speed double heterojunction bipolar transistors [1], solar cells [2], quantum well (QW) lasers [3] and photodetectors [4].…”

Photoluminescence and band offset of type-II AlGaAsSb/InP heterostructures

“…In this context, the importance of GaAsSb became apparent in the last few decades because of the large band gap tuning and its type-II band alignment relative to GaAs, InP and InGaAs. This material has been successfully applied to double heterojunction bipolar transistors (DHBTs) [1], type-II multiple quantum wells (MQWs) [2], vertical cavity surface emitting lasers (VCSELs) [3], photodiodes [4] and quantum cascade lasers [5]. The design of devices and the simulation of their performances, require the knowledge of the heterojunction interface properties.…”