Si–MoS2 Vertical Heterojunction for a Photodetector with High Responsivity and Low Noise Equivalent Power (original) (raw)
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Recently, chemical vapor deposition-grown molybdenum disulfide (MoS 2) has been actively employed for MoS 2 /Si-wafer heterojunction (HJT) photodetectors due to the attractive optoelectronic properties. However, the MoS 2 /Si HJT is not so advantageous in that it exhibits low photoresponse due to the low light absorption despite the simple device structure. In addition, there is a limitation in achieving highquality MoS 2 films due to the defects at the MoS 2 /Si interface developed during the transfer of the MoS 2 films to the target substrate, resulting from the restriction of the direct growth on the Si wafer. Here, we first report successful direct growth of single-and multi-layer MoS 2 films on Si quantum dots (SQDs) multilayers (MLs) embedded SiO 2 (SQDs:SiO 2 MLs) substrates. The multilayer MoS 2 /SQDs HTJ photodiodes show response speed of rise time:~60 ns/fall time:~756 ns, highest than ever achieved, and detectivity of 6.1 Â 10 13 cm Hz 1/2 W À1. This excellent performance can be attributed to well formation of the HJT at the MoS 2 /SQDs:SiO 2 interface by the direct growth, resulting in the reduction of the defects, thereby facilitating the carrier transport, and high light absorptivity of the SQDs:SiO 2 MLs.
MoS2 Based Photodetectors: A Review
Sensors, 2021
Photodetectors based on transition metal dichalcogenides (TMDs) have been widely reported in the literature and molybdenum disulfide (MoS2) has been the most extensively explored for photodetection applications. The properties of MoS2, such as direct band gap transition in low dimensional structures, strong light–matter interaction and good carrier mobility, combined with the possibility of fabricating thin MoS2 films, have attracted interest for this material in the field of optoelectronics. In this work, MoS2-based photodetectors are reviewed in terms of their main performance metrics, namely responsivity, detectivity, response time and dark current. Although neat MoS2-based detectors already show remarkable characteristics in the visible spectral range, MoS2 can be advantageously coupled with other materials to further improve the detector performance Nanoparticles (NPs) and quantum dots (QDs) have been exploited in combination with MoS2 to boost the response of the devices in th...
Bias-dependent photoresponsivity of multi-layer MoS2 phototransistors
Nanoscale Research Letters, 2017
We studied the variation of photoresponsivity in multi-layer MoS2 phototransistors as the applied bias changes. The photoresponse gain is attained when the photogenerated holes trapped in the MoS2 attract electrons from the source. Thus, the photoresponsivity can be controlled by the gate or drain bias. When the gate bias is below the threshold voltage, a small amount of electrons are diffused into the channel, due to large barrier between MoS2 and source electrode. In this regime, as the gate or drain bias increases, the barrier between the MoS2 channel and the source becomes lower and the number of electrons injected into the channel exponentially increases, resulting in an exponential increase in photoresponsivity. On the other hand, if the gate bias is above the threshold voltage, the photoresponsivity is affected by the carrier velocity rather than the barrier height because the drain current is limited by the carrier drift velocity. Hence, with an increase in drain bias, the c...