Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors

We study the effect of temperature and doping in Si-based GeSn heterojunction phototransistors (HPTs) for low-power-consuming, low-cost, and high-speed mid-infrared (MIR) applications. The incorporation of <inline-formula><tex-math notation="LaTeX">${\rm{G}}{{\rm{e}}_{1 - x}}{\...

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Main Authors: Harshvardhan Kumar, Rikmantra Basu, Guo-En Chang
Format: Article
Language:English
Published: IEEE 2020-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/9099040/
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author Harshvardhan Kumar
Rikmantra Basu
Guo-En Chang
author_facet Harshvardhan Kumar
Rikmantra Basu
Guo-En Chang
author_sort Harshvardhan Kumar
collection DOAJ
description We study the effect of temperature and doping in Si-based GeSn heterojunction phototransistors (HPTs) for low-power-consuming, low-cost, and high-speed mid-infrared (MIR) applications. The incorporation of <inline-formula><tex-math notation="LaTeX">${\rm{G}}{{\rm{e}}_{1 - x}}{\rm{S}}{{\rm{n}}_x}$</tex-math></inline-formula> alloy in the base of our HPTs significantly shortens the emitter-to-collector transit time, leading to high cut-off frequency (<inline-formula><tex-math notation="LaTeX">${f_T}$</tex-math></inline-formula>) due to an increase in mobility. Furthermore, the <inline-formula><tex-math notation="LaTeX">${\rm{G}}{{\rm{e}}_{1 - x}}{\rm{S}}{{\rm{n}}_x}$</tex-math></inline-formula> base extends the optical detection over a wide range (up to 2500 nm) due to the shrinkage of the bandgap energy caused by alloying with Sn. Additionally, spectral responsivity increases with Sn alloying due to the increased absorption coefficient. Our results show that <inline-formula><tex-math notation="LaTeX">${f_T}$</tex-math></inline-formula> and responsivity are strongly dependent not only on doping but also on temperature. The impact of temperature on the noise behavior of phototransistors was also analyzed for frequencies up to 100 GHz. As the temperature increased, the signal-to-noise ratio (SNR) decreased; however, spectral responsivity significantly improved. The high SNR, responsivity, and <inline-formula><tex-math notation="LaTeX">${f_T}$</tex-math></inline-formula> values of the GeSn HPT make it a potential candidate for future Si-based uncooled high-speed MIR photodetection.
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series IEEE Photonics Journal
spelling doaj-art-a2b515e1ce2e487dadeee61bb4f86a0b2025-08-20T03:32:37ZengIEEEIEEE Photonics Journal1943-06552020-01-0112311410.1109/JPHOT.2020.29968089099040Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction PhototransistorsHarshvardhan Kumar0https://orcid.org/0000-0002-4803-810XRikmantra Basu1Guo-En Chang2https://orcid.org/0000-0002-3739-5451Electronics and Communication Engineering Department, National Institute of Technology Delhi, Institutional Area, IAMR Campus, New Delhi, IndiaElectronics and Communication Engineering Department, National Institute of Technology Delhi, Institutional Area, IAMR Campus, New Delhi, IndiaDepartment of Mechanical Engineering and Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chiayi County, TaiwanWe study the effect of temperature and doping in Si-based GeSn heterojunction phototransistors (HPTs) for low-power-consuming, low-cost, and high-speed mid-infrared (MIR) applications. The incorporation of <inline-formula><tex-math notation="LaTeX">${\rm{G}}{{\rm{e}}_{1 - x}}{\rm{S}}{{\rm{n}}_x}$</tex-math></inline-formula> alloy in the base of our HPTs significantly shortens the emitter-to-collector transit time, leading to high cut-off frequency (<inline-formula><tex-math notation="LaTeX">${f_T}$</tex-math></inline-formula>) due to an increase in mobility. Furthermore, the <inline-formula><tex-math notation="LaTeX">${\rm{G}}{{\rm{e}}_{1 - x}}{\rm{S}}{{\rm{n}}_x}$</tex-math></inline-formula> base extends the optical detection over a wide range (up to 2500 nm) due to the shrinkage of the bandgap energy caused by alloying with Sn. Additionally, spectral responsivity increases with Sn alloying due to the increased absorption coefficient. Our results show that <inline-formula><tex-math notation="LaTeX">${f_T}$</tex-math></inline-formula> and responsivity are strongly dependent not only on doping but also on temperature. The impact of temperature on the noise behavior of phototransistors was also analyzed for frequencies up to 100 GHz. As the temperature increased, the signal-to-noise ratio (SNR) decreased; however, spectral responsivity significantly improved. The high SNR, responsivity, and <inline-formula><tex-math notation="LaTeX">${f_T}$</tex-math></inline-formula> values of the GeSn HPT make it a potential candidate for future Si-based uncooled high-speed MIR photodetection.https://ieeexplore.ieee.org/document/9099040/Cut-off frequencydopingGeSn alloyheterojunction phototransistor (HPT)responsivitytemperature
spellingShingle Harshvardhan Kumar
Rikmantra Basu
Guo-En Chang
Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors
IEEE Photonics Journal
Cut-off frequency
doping
GeSn alloy
heterojunction phototransistor (HPT)
responsivity
temperature
title Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors
title_full Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors
title_fullStr Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors
title_full_unstemmed Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors
title_short Impact of Temperature and Doping on the Performance of <inline-formula><tex-math notation="LaTeX">${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$</tex-math></inline-formula> Heterojunction Phototransistors
title_sort impact of temperature and doping on the performance of inline formula tex math notation latex bf ge bf g bf e 1 boldsymbol x bf s bf n boldsymbol x bf ge tex math inline formula heterojunction phototransistors
topic Cut-off frequency
doping
GeSn alloy
heterojunction phototransistor (HPT)
responsivity
temperature
url https://ieeexplore.ieee.org/document/9099040/
work_keys_str_mv AT harshvardhankumar impactoftemperatureanddopingontheperformanceofinlineformulatexmathnotationlatexbfgebfgbfe1boldsymbolxbfsbfnboldsymbolxbfgetexmathinlineformulaheterojunctionphototransistors
AT rikmantrabasu impactoftemperatureanddopingontheperformanceofinlineformulatexmathnotationlatexbfgebfgbfe1boldsymbolxbfsbfnboldsymbolxbfgetexmathinlineformulaheterojunctionphototransistors
AT guoenchang impactoftemperatureanddopingontheperformanceofinlineformulatexmathnotationlatexbfgebfgbfe1boldsymbolxbfsbfnboldsymbolxbfgetexmathinlineformulaheterojunctionphototransistors