10.1021/acsnano.7b00972.s001 Mengyu Chen Mengyu Chen Haipeng Lu Haipeng Lu Nema M. Abdelazim Nema M. Abdelazim Ye Zhu Ye Zhu Zhen Wang Zhen Wang Wei Ren Wei Ren Stephen V. Kershaw Stephen V. Kershaw Andrey L. Rogach Andrey L. Rogach Ni Zhao Ni Zhao Mercury Telluride Quantum Dot Based Phototransistor Enabling High-Sensitivity Room-Temperature Photodetection at 2000 nm American Chemical Society 2017 detectivity gas-injection synthesis method mercury Telluride Quantum Dot HgTe QDs detection devices phototransistor structure 2.1 μ m epitaxial-grown photodetectors silicon technologies QD photodetectors solution processability 2000 nm Near-to-mid-infrared photodetection technologies performance bottleneck carbon monoxide gas 2 μ m wavelength range room-temperature device response quantum dot QD phototransistor 2 kHz modulation frequency detection technologies photoluminescence quantum technology device engineering scalable fabrication application requirements Phototransistor Enabling High-Sensitivity Room-Temperature Photodetection photoluminescence peak gas concentration 2017-05-19 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Mercury_Telluride_Quantum_Dot_Based_Phototransistor_Enabling_High-Sensitivity_Room-Temperature_Photodetection_at_2000_nm/5077849 Near-to-mid-infrared photodetection technologies could be widely deployed to advance the infrastructures of surveillance, environmental monitoring, and manufacturing, if the detection devices are low-cost, in compact format, and with high performance. For such application requirements, colloidal quantum dot (QD) based photodetectors stand out as particularly promising due to the solution processability and ease of integration with silicon technologies; unfortunately, the detectivity of the QD photodetectors toward longer wavelengths has so far been low. Here we overcome this performance bottleneck through synergistic efforts between synthetic chemistry and device engineering. First, we developed a fully automated aprotic solvent, gas-injection synthesis method that allows scalable fabrication of large sized HgTe QDs with high quality, exhibiting a record high photoluminescence quantum yield of 17% at the photoluminescence peak close to 2.1 μm. Second, through gating a phototransistor structure we demonstrate room-temperature device response to reach >2 × 10<sup>10</sup> cm Hz<sup>1/2</sup> W<sup>–1</sup> (at 2 kHz modulation frequency) specific detectivity beyond the 2 μm wavelength range, which is comparable to commercial epitaxial-grown photodetectors. To demonstrate the practical application of the QD phototransistor, we incorporated the device in a carbon monoxide gas sensing system and demonstrated reliable measurement of gas concentration. This work represents an important step forward in commercializing QD-based infrared detection technologies.