期刊
NANO LETTERS
卷 18, 期 12, 页码 7901-7908出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.nanolett.8b03775
关键词
Nanowires; InAs; InP; SWIR; photodetector; heterojunction; dark current
类别
资金
- National Science Foundation [ECCS-1509801]
- Air Force Office of Scientific Research [FA9550-15-1-0324]
- Ser Cymru National Research Network in Advanced Engineering and Materials
In this work, we demonstrate an InAs nanowire photo detector at short-wavelength infrared (SWIR) composed of vertically oriented selective-area InAs nanowire photoabsorber arrays on InP substrates, forming InAs InP heterojunctions. We measure a rectification ratio greater than 300 at room temperature, which indicates a desirable diode performance. The dark current density, normalized to the area of nanowire heterojunctions, is 130 mA/cm(2) at a temperature of 300 K and a reverse bias of 0.5 V, making it comparable to the state-of-the-art bulk InAs p-i-n photodiodes. An analysis of the Arrhenius plot of the dark current at reverse bias yields an activation energy of 175 meV from 190 to 300 K, suggesting that the Shockley-Read-Hall (SRH) nonradiative current is the primary contributor to the dark current. By using three-dimensional electrical simulations, we determine that the SRI-I non radiative current originates from the acceptor-like surface traps at the nanowire-passivation heterointerfaces. The spectral response at room temperature is also measured, with a clear photodetection signature observed at wavelengths up to 2.5 mu m. This study provides an understanding of dark current for small band gap selective-area nanowires and paves the way to integrate these improved nanostructured photoabsorbers on large band gap substrates for high-performance photodetectors at SWIR.
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