Correlation between the time constant of a photoreflectance signal and the quantum efficiency of a p-n junction

Farzin, Behnam Zeinalvand; Lee, DongKun; Kim, Geun Hyeong; Ha, Jaedu; Kim, Jong Su; Kim, Yeongho; Lee, Sang Jun

doi:10.1007/s40042-023-00742-9

Cited by 3 publications

(1 citation statement)

References 32 publications

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“…However, photoreflectance (PR), known as a powerful contactless spectroscopy technique, can reveal various features in semiconductor structures, particularly interface and surface characteristics [20]. This valuable information includes optical transitions [21], builtin electric fields [22], defect densities [23], strain influence [24], quantum efficiency [25], and more. Several works have also investigated the dynamics of carriers in structures such as photodiodes by employing a similar experimental setup and observing the transient behavior of reflectivity [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Photoreflectance Analysis of InAsPSb/InGaAs Multi-Quantum Well LED Structures with Different Well/Barrier Numbers

Zeinalvand Farzin,

Seyedein Ardebili,

Kang

et al. 2024

Photonics

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InAsPSb is an emerging material used as an efficient barrier in quantum well structures, and the resulting devices can be employed in the mid-infrared region of the electromagnetic spectrum. This study investigates the photoreflectance spectra of two InAsPSb/InGaAs multi-quantum well light-emitting diodes with 6 and 15 quantum well periods. The photoreflectance of the samples was analyzed at various temperatures and excitation powers. By examining the Franz-Keldysh oscillations in the spectra, we explored the influence of the number of well layers on the electric field strength in the junction. The results showed that the number of quantum wells can influence the electric field at the junction, potentially impacting the overall performance of the devices. The simulation of the electric field strength aligns with the results of the photoreflectance analysis. This suggests that the field extracted from Franz-Keldysh oscillations characterizes the field inside the multi-quantum wells, offering potential reasons for the observed effects on the number of multi-quantum wells in the field.

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Section: Introductionmentioning

confidence: 99%

Photoreflectance Analysis of InAsPSb/InGaAs Multi-Quantum Well LED Structures with Different Well/Barrier Numbers

Zeinalvand Farzin,

Seyedein Ardebili,

Kang

et al. 2024

Photonics

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Phase-sensitive analysis of a two-color infrared photodetector using photoreflectance spectroscopy

Zeinalvand Farzin,

Lee,

Kang

et al. 2023

Journal of Applied Physics

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The phase diagrams of photoreflectance spectra were investigated for an InGaAs two-color infrared photodetector. The diagrams for a high excitation intensity revealed that the spectrum is multi-component. The origin of these components was investigated, and the photoreflectance spectra and phase diagrams were also measured for an angle-polished version at different depths. With the help of the polished sample, the variation of the phase delay angles and the trapping time constants was tracked for different depths. Additionally, the polished version enables us to find a confirmation for the origins of the multi-component nature of the whole phase diagram. It can be concluded that when the phase delays or time constants of various components are very close, more attention should be paid to interfering with the phase-sensitive investigations of layered materials. As a main result, the consistency of the phase delay with interface trap densities was confirmed qualitatively. Using a reciprocal space map of the sample, this result can be a piece of experimental evidence for a correlation between the photoreflectance time constant and trap densities in the junctions. This non-contact method enables the characterization of layered devices, offering a valuable tool for achieving high-performance devices.

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Investigation of capacitance for InAs/GaAs quantum dot solar cells by photoreflectance

Zeinalvand Farzin,

Kim,

Kim

et al. 2024

Journal of Vacuum Science &Amp; Technology A

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The study provides experimental validation for the correlation between the photoreflectance signal’s time constant and the capacitances of various p-n junction quantum-dot solar cells. Photoreflectance spectra were measured on four structures with varying InAs/GaAs quantum dot layer thicknesses (1.7–3 monolayers), and time constants were extracted from the phase diagrams. A linear relationship was observed between these time constants and the cells’ capacitances. Analysis of the phase diagrams for different chopping frequencies revealed that this approach allows for the assessment of capacitances of a sample set through a single photoreflectance measurement. These findings underscore the potential of photoreflectance as a straightforward, contactless technique for comparing junction capacitance across samples. Furthermore, this work could enhance our understanding of photoreflectance in solar cell characterization and present a practical tool for evaluating capacitance in various optoelectronic devices, broadening the utility of nondestructive characterization techniques.

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Correlation between the time constant of a photoreflectance signal and the quantum efficiency of a p-n junction

Cited by 3 publications

References 32 publications

Photoreflectance Analysis of InAsPSb/InGaAs Multi-Quantum Well LED Structures with Different Well/Barrier Numbers

Photoreflectance Analysis of InAsPSb/InGaAs Multi-Quantum Well LED Structures with Different Well/Barrier Numbers

Phase-sensitive analysis of a two-color infrared photodetector using photoreflectance spectroscopy

Investigation of capacitance for InAs/GaAs quantum dot solar cells by photoreflectance

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