TY - JOUR
T1 - Ultrafast intrinsic photoresponse and direct evidence of sub-gap states in liquid phase exfoliated MoS2 thin films
AU - Ghosh, Sujoy
AU - Winchester, Andrew
AU - Muchharla, Baleeswaraiah
AU - Wasala, Milinda
AU - Feng, Simin
AU - Elias, Ana Laura
AU - Krishna, M. Bala Murali
AU - Harada, Takaaki
AU - Chin, Catherine
AU - Dani, Keshav
AU - Kar, Swastik
AU - Terrones, Mauricio
AU - Talapatra, Saikat
PY - 2015/7/15
Y1 - 2015/7/15
N2 - 2-Dimensional structures with swift optical response have several technological advantages, for example they could be used as components of ultrafast light modulators, photo-detectors, and optical switches. Here we report on the fast photo switching behavior of thin films of liquid phase exfoliated MoS 2, when excited with a continuous laser of λ=658nm (E=1.88eV), over a broad range of laser power. Transient photo-conductivity measurements, using an optical pump and THz probe (OPTP), reveal that photo carrier decay follows a bi-exponential time dependence, with decay times of the order of picoseconds, indicating that the photo carrier recombination occurs via trap states. The nature of variation of photocurrent with temperature confirms that the trap states are continuously distributed within the mobility gap in these thin film of MoS2, and play a vital role in influencing the overall photo response. Our findings provide a fundamental understanding of the photo-physics associated with optically active 2D materials and are crucial for developing advanced optoelectronic devices.
AB - 2-Dimensional structures with swift optical response have several technological advantages, for example they could be used as components of ultrafast light modulators, photo-detectors, and optical switches. Here we report on the fast photo switching behavior of thin films of liquid phase exfoliated MoS 2, when excited with a continuous laser of λ=658nm (E=1.88eV), over a broad range of laser power. Transient photo-conductivity measurements, using an optical pump and THz probe (OPTP), reveal that photo carrier decay follows a bi-exponential time dependence, with decay times of the order of picoseconds, indicating that the photo carrier recombination occurs via trap states. The nature of variation of photocurrent with temperature confirms that the trap states are continuously distributed within the mobility gap in these thin film of MoS2, and play a vital role in influencing the overall photo response. Our findings provide a fundamental understanding of the photo-physics associated with optically active 2D materials and are crucial for developing advanced optoelectronic devices.
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U2 - 10.1038/srep11272
DO - 10.1038/srep11272
M3 - Article
C2 - 26175112
SN - 2045-2322
VL - 5
JO - Scientific reports
JF - Scientific reports
M1 - 11272
ER -