Baile Chen

SWIR/MWIR InP-Based p-i-n Photodiodes With InGaAs/GaAsSb Type-II Quantum Wells

This paper presents the performance characteristics of InP-based p-i-n photodiodes with strain-compensated and lattice-matched InGaAs/GaAsSb type-II multiple quantum well (MQW) absorption regions. The results show that photodiodes with strain-compensated and lattice-matched absorption regions have optical response out to 3.4 and 2.8 μm with dark current densities of 9.7 and 1.66 mA cm-2,respectively, at 290 K under -0.5 V reverse bias. The carrier transport mechanism responsible for the difference in responsivity and detectivity between strain-compensated and lattice-matched InGaAs/GaAsSb MQWs is discussed.

Demonstration of a Room-Temperature InP-Based Photodetector Operating Beyond 3

An InP-based p-i-n photodiode with optical response out to 3.4 μm was designed and grown by molecular beam epitaxy (MBE). One hundred pairs of 7-nm In_0.34Ga_0.66As/5-nm GaAs_0.25Sb_0.75 quantum wells strain compensated to InP were used as the absorption region. The device showed a dark current density of 9.6 mA/cm² under -0.5-V reverse bias, a responsivity of 0.03 A/W, and a detectivity of 2.0 × 10⁸ cm·Hz^1/2·W^-1 at 3 μm at 290 K.

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We report on InP-based p-type/intrinsic/n-type (PIN) photodiodes with a novel strain-compensated type-II InGaAs/GaAsSb quantum well active region. The device has optical response out to 3.0 μm, specific detectivity (D*) of 7.73×10(9) cm Hz(0.5)/W at 290 K for 2.7 μm. These preliminary results show that this novel strain-compensated approach leads to similar performance when compared to a conventional strain-compensated approach.

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Multiple quantum well (MQW) photodiodes based on the InGaAs/GaAsSb material system are emerging as viable candidates for mid infrared detection. A critical issue for these devices is dark current caused by defects within the material. In this work, low frequency noise spectroscopy and random telegraph signal characterization were used to characterize defect levels in MQW photodiodes. Three traps, located at 0.14 eV (Ea), 0.34 eV (Eb), and 0.43 eV (Ec), were identified from the measured noise. Ea is associated with bulk InGaAs, Eb may be associated with bulk GaAsSb, and Ec is localized at the InGaAs/GaAsSb heterointerface.

InP-based short-wave infrared and midwave infrared photodiodes using a novel type-II strain-compensated quantum well absorption region

Different type-II InGaAs/GaAsSb quantum well design structures on InP substrate for mid-infrared emission has been modeled by six band k•p method. The dispersion relations, optical matrix element, optical gain and spontaneous emission rate are calculated. The effects of the parameters of quantum wells (thickness, composition) and properties of cladding layers were investigated. For injected carrier concentration of 5×1012 cm-2, peak gain values around 2.6-2.7 μm wavelengths of the order of 1000 cm-1 can be achieved, which shows that type-II InGaAs/GaAsSb quantum wells are suitable for infrared laser operation beyond 2μm at room temperature.

Bulk and interfacial deep levels observed in In0.53Ga0.47As/GaAs0.5Sb0.5 multiple quantum well photodiode

Monte Carlo simulation is performed on a three-stage avalanche photodiode (APD). Two modifications to further reduce the excess noise are proposed.

Modeling of the type-II InGaAs/GaAsSb quantum well designs for mid-infrared laser diodes by k•p method

GaInAs/GaAsSb type-II multiple quantum wells (MQWs) grown on InP substrates by molecular beam epitaxy (MBE) were investigated for potential use in p-i-n photodiodes operating in the mid-infrared spectral region. In these quantum well structures, electrons and holes are spatially separated. The resulting spatially indirect type-II detection occurs at longer wavelength than the spatially direct intraband recombination in either GaInAs or GaAsSb. A 4-band k · p Hamiltonian model was employed to calculate the detection wavelengths and wavefunction overlaps. A p-i-n structure with 100 pairs of Ga0.66In034As (~7.0 nm)/GaAs0.25Sb0.75 (~5.0 nm) MQWs structure with operation wavelength of above 3.0 μm was designed and grown by MBE. The compressively strained GaAsSb layers are strain-compensated by tensile strained GaInAs. Photo response of above 3 μm was observed by room temperature responsivity measurements.

Numerical simulation of InAlAs/InAlGaAs tandem avalanche photodiodes

A novel active region design based on a type-II InGaAs/GaAsSbBi quantum wells on GaAs substrate is proposed and studied in this work. The band structures of the InGaAs/GaAsSbBi type-II quantum wells are studied based on a self-consistent 14-band k·p model. The electronic and optical properties of dilute-bismide InGaAs/GaAsSbBi type-II quantum well structures are investigated theoretically. Moreover, the room temperature gain characteristics of the laser active region are studied with different Bi composition. The theoretical results indicate that adding Bi into InGaAs/GaAsSb type-II active regions on GaAs substrate extends the laser emission wavelength beyond 1550nm without sacrificing the peak gain value. It is shown that these type-II quantum well structures are suitable for 1550nm wavelength region operation at room temperature.

Design and characterization of strain-compensated InGaAs/GaAsSb type-II MQW structure with operation wavelength at ~3μm

In this paper, a new method of studying the carrier transport is proposed and demonstrated. We designed two structures to study the carrier transport mechanism in InP-based photodiodes with InGaAs/GaAsSb type-II quantum well absorption regions. Based on the comparison of the responsivity of the two different device structures, we concluded that thermionic emission is the dominant carrier transport mechanism for these quantum well structures.

Optical gain analysis of GaAs-based InGaAs/GaAsSbBi type-II quantum wells lasers

InP-based multiple quantum well (MQW) photodiodes in the InGaAs/GaAsSb material system are promising for mid-infrared detection [1]; by including strain in these devices, the detection wavelength has been extended to beyond 3 μm [2]. However, owing to the relative immaturity of these materials, there have been few reports of the characteristics of defects in this system and their impact on device performance, especially under strain and at material compositions appropriate for MQW detectors. In this work, In0.53Ga0.47As/GaAs0.5Sb0.5 (lattice-matched) and In0.34Ga0.66As/GaAs0.25Sb0.75 (strain-compensated) MQW photodiodes are evaluated using low-frequency noise spectroscopy (LFNS) and deep level transient spectroscopy (DLTS) to detect and extract the properties of defect levels, and their impact on dark current and noise performance of the photodiodes is evaluated.