Sensitivity of resonant tunneling diode photodetectors
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We have studied the sensitivity of AlGaAs/GaAs double barrier resonant tunneling diode photodetectors with an integrated GaInNAs absorption layer for light sensing at the telecommunication wavelength of λ=1.3 µm for illumination powers from pico to micro Watts. The sensitivity decreases nonlinearly with power. An illumination power increase of seven orders of magnitude leads to a reduction of the photocurrent sensitivity from SI =5.82 × 103 A/W to 3.2 A/W. We attribute the nonlinear sensitivity-power dependence to an altered local electrostatic potential due to hole-accumulation that on the one hand tunes the tunneling current, but on the other hand affects the lifetime of photogenerated holes. In particular, the lifetime decreases exponentially with increasing hole-population. The lifetime reduction results from an enhanced electrical field, a rise of the quasi-Fermi level and an increased energy splitting within the triangular potential well. The non-constant sensitivity is a direct result of the non-constant lifetime. Based on these findings, we provide an expression that allows to calculate the sensitivity as a function of illumination power and bias voltage, show a way to model the time-resolved photocurrent, and determine the critical power up to which the resonant tunneling diode photosensor sensitivity can be assumed constant.
Pfenning , A , Hartmann , F , Langer , F , Kamp , M , Hoefling , S & Worschech , L 2016 , ' Sensitivity of resonant tunneling diode photodetectors ' Nanotechnology , vol. 27 , no. 35 , 355202 . DOI: 10.1088/0957-4484/27/35/355202
© 2016, IOP Publishing Ltd. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at iopscience.iop.org / https://dx.doi.org/10.1088/0957-4484/27/35/355202
DescriptionThe authors are grateful for financial support by the BMBF via national project EIPHRIK (FKZ: 13N10710) and the European Union (FPVII (2007-2013) under Grant Agreement No. 318287 LANDAUER).
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