Impact of ternary capping on p-i-p InAs/GaAs quantum-dot infrared photodetectors

Self-assembled InAs/GaAs quantum dot infrared photodetectors (QDIPs) have been proved suitable candidates for infrared photodetectors due to their excellent carrier confinement, normal-incidence absorption, reduced electron– phonon scattering and long excited carrier lifetime. This study investigates the effect of ternary (InGaAs) capping on InAs/GaAs p-i-p QDIP grown on semi-insulating GaAs substrate using Molecular Beam Epitaxy (MBE). The performance of InAs/GaAs QDIP (device A) is compared with InAs/InGaAs/GaAs QDIP (device B), in which ternary (InGaAs) capping of 6nm thickness was introduced just above the InAs quantum dot layer. The room temperature photoluminescense peak was observed at a wavelength of 1139.7nm and 1310.1nm for sample A and B, respectively. The activation energy was calculated to be 222.93 and 142.325 meV for sample A and B, respectively. From fabricated single pixel detectors, the dark current densities measured for an applied bias of -0.5V at 13 K were 0.5mA/cm2 and 0.54A/cm2 for device A and B, respectively. Devices exhibited spectral response peaks around 1.93μm and 1.52 μm for device A and device B, respectively. The measured peak can be attributed to the transition between ground state of hole to split off band. At 175K, the peak responsivity calculated was 5.8 A/W for GaAs capped device (A) as compared to 0.55 A/W for InGaAs capped device (B). Highest operating temperature exhibited by GaAs capped device A was 200K. Since the observed dark current densities was higher in comparison with device A, the highest operating temperature observed for device B was limited to 175K.

[1]  N. Browning,et al.  Investigation of strain in self-assembled multilayer InAs/GaAs quantum dot heterostructures , 2010 .

[2]  S. Saha,et al.  Binary and ternary capped In(Ga)As/GaAs self-assembled quantum dots: An annealing study , 2018 .

[3]  S. Chakrabarti,et al.  Enhancement of device performance by using quaternary capping over ternary capping in strain-coupled InAs/GaAs quantum dot infrared photodetectors , 2015 .

[4]  A. E. Wetsel,et al.  Observation of discrete electronic states in a zero-dimensional semiconductor nanostructure. , 1988, Physical review letters.

[5]  Subhananda Chakrabarti,et al.  Characteristics of a tunneling quantum-dot infrared photodetector operating at room temperature , 2005 .

[6]  S. Chakrabarti,et al.  Thermal stability of the peak emission wavelength in multilayer InAs/GaAs QDs capped with a combination capping of InAlGaAs and GaAs. , 2011, Journal of nanoscience and nanotechnology.

[7]  S. Chakrabarti,et al.  Effect of InAlGaAs and GaAs combination barrier thickness on the stacking of InAs/GaAs quantum dot heterostructure grown by MBE , 2009 .

[8]  M. Sugawara.  Self-assembled InGaAs/GaAs, quantum dots , 1999 .

[9]  Nikolai N. Ledentsov,et al.  InAs/InGaAs/GaAs quantum dot lasers of 1.3 μm range with enhanced optical gain , 2003 .

[10]  Yoshiaki Nakata,et al.  Low threshold current operation of self-assembled InAs/GaAs quantum dot lasers by metal organic chemical vapour deposition , 2003 .

[11]  A. Stintz,et al.  Low-threshold current density 1.3-μm InAs quantum-dot lasers with the dots-in-a-well (DWELL) structure , 2000, IEEE Photonics Technology Letters.

[12]  Hemant Ghadi,et al.  A detail investigation on quaternary and ternary capped strain coupled quantum dots based infrared photodetectors and effect of rapid thermal annealing temperature , 2015, Commercial + Scientific Sensing and Imaging.

[13]  Sunoh Kim,et al.  InAs/GaAs p-i-p quantum dots-in-a-well infrared photodetectors operating beyond 200 K , 2014 .

[14]  Mikhail V. Maximov,et al.  Tuning quantum dot properties by activated phase separation of an InGa(Al)As alloy grown on InAs stressors , 2000 .