Analysis of Low-Frequency Noise in Quantum Dot/Metal-Oxide Phototransistors with Metal Chalcogenide Interfaces

초록

Low-frequency noise measurements are carried out to investigate optoelectronic characteristics of CdSe quantum dot (QD)/indium-gallium-zinc-oxide (IGZO) heterostructured hybrid phototransistor with respect to various QD surface ligands, such as chalcometallate ligands (Sn₂S₆4- and Sn₂Se₆4-) and thiocyanate (SCN-). It is found that Sn₂S₆4- and Sn₂Se₆4--capped QD/IGZO phototransistors show enhanced optoelectronic characteristics such as responsivity (<italic>R</italic>) of 3.06&#x00D7;103 A W-1 and 8.8&#x00D7;102 A W-1, respectively, and photodetectivity (<italic>D</italic>*) of 2.1&#x00D7;1013 Jones and 6.18&#x00D7;1011 Jones, respectively, compared with SCN--capped CdSe QD/IGZO phototransistors (<italic>R</italic> of 1.21&#x00D7;103 A W-1 and <italic>D</italic>* of 2.02&#x00D7;1011 Jones). Independently, all these devices exhibit 1/<italic>f</italic> low-frequency noise dependence in the subthreshold, ohmic, and saturation regimes. In particular, in the ohmic and saturation regime, the low-frequency noise properties follow the bulk mobility fluctuation mechanism for the chalcometallate ligands-based devices, while carrier number fluctuation model is dominant for the SCN--based devices. Thus, low-frequency noise analysis may provide meaningful information to evaluate important parameters for nanomaterial-based optoelectronics. IEEE

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