Ge/Si photodetectors and group IV alloy based photodetector materials

Abstract

Photodetectors using Si, Ge and their alloys with other group IV elements are of current interest for application in telecommunication as well as in optical interconnects. We have presented in this paper our work on resonant cavity enhanced Si/SiGe multiple Quantum Well and Ge Schottky photodetectors. Calculated values of external quantum efficiency for GeSiC based photodetectors are also reported. Tensile strained Ge layers grown with suitable barriers show direct gap type I band alignment. Predicted performance of photodetectors using strong Quantum Confined Stark Effect and Franz-Keldysh Effect in these structures and properties related to photodetection using these new materials are also described.Keywords Photodetectors · Ge/SiGe quantum wells · Direct gap in Ge · Quantum confined stark effect · Franz Keldysh effect · GeSn and SGeSn alloys

Tuning the Electro-optical Properties of Germanium Nanowires by Tensile Strain

“…1 In addition, due to the small difference between direct and indirect bandgap energy, Ge appeared to be a promising material for next generation on-chip light sources and detectors 2,3 and thus triggered a lot of activities for photonic applications. 4−11 Thereby the main issue is to overcome the inefficient light emission of an indirect semiconductor.…”

GeSn/SiGeSn RCE photodetectors: A comparative study based on Franz-Keldysh effect and quantum confined stark effect

“…They reported the TM and TE absorption spectra without electric field as well as with fields in the range 2 MV/m -12 MV/m with 2 MV/m steps. We have used a simple procedure to reproduce the reported absorption spectra, which has been prescribed in [10] in connection with excitonic electroabsorptions in GaAs-AlGaAs QWs and then applied in [17] for the Ge-Si MQW structure studied by Kuo et al [11]. In this method the sum of two Gaussian distributions and a broadened two dimensional (2D) continuum is used to fit the curves.…”

“…In this method the sum of two Gaussian distributions and a broadened two dimensional (2D) continuum is used to fit the curves. To describe the absorption at room temperature we have used the following expression [17] that takes into account two discrete excitonic transitions (hh-e, and lh-e) as well as absorption by the 2D continuum states: …”

Strain distribution in single, suspended germanium nanowires studied using nanofocused x-rays

“…The need for high-efficiency light emitting semiconductor devices based on silicon technology drives the efforts to alter the band structure of germanium, which has proven to be a good companion for state of the art silicon technology [1][2][3].…”