Noise analysis of optimized \({\text{Ge}}/{\text{Ge}}_{{1 - {\text{x}}}} {\text{Sn}}_{\text{x}} /{\text{Ge}}\) p–n–p heterojunction phototransistors for long-wavelength optical receivers

  • Rikmantra Basu
  • Harshvardhan KumarEmail author
Part of the following topical collections:
  1. Numerical Simulation of Optoelectronic Devices 2018


Present literature investigates noise analysis and optimal design for \({\text{Ge}}/{\text{Ge}}_{1 - {\text{x}}} {\text{Sn}}_{\text{x}} /{\text{Ge}}\) based p–n–p heterojunction phototransistors (HPT) for long-wavelength optical receivers. We calculate gain, noise powers, signal-to-noise ratio, absorption coefficient and optical responsivity of proposed GeSn-based HPT and investigate their dependence on various structural parameters to optimize the design. The proposed HPT incorporates \({\text{Ge}}_{{1 - {\text{x}}}} {\text{Sn}}_{\text{x}}\) alloy in the base layer as the active layer, allow to extend the photo detection range from near infrared to mid-infrared to achieve a wide range of detection. The results show that the signal-to-noise ratio (SNR) is strongly dependent on the operating frequency and the introduction of Sn in the base layer can improve the signal-to-noise ratio in the high-frequency region. The calculated results also show that even in the presence of small defects and misfit dislocations at the heterointerfaces, high SNR is still achievable for the proposed structure.


GeSn-alloy HPTs Voltage gain SNR Absorption coefficient Responsivity 



The work is supported by DST-SERB, Govt. of India, under the Early Career Research Award Scheme 2017 (FILE No. ECR/2017/000794). Also, the authors would like to acknowledge support by GITA/DST through the project under India-Taiwan Programme of Cooperation in Science and Technology (Ref No. GITA/DST/TWN/P-63/2015).


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Electronics and Communication EngineeringNational Institute of Technology DelhiNew DelhiIndia

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