期刊
IEEE TRANSACTIONS ON NANOTECHNOLOGY
卷 18, 期 -, 页码 781-789出版社
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/TNANO.2019.2931814
关键词
Bilayer graphene; HgCdTe; heterojunction; infrared; photodetector; quantum efficiency
We present novel p(+)-bilayer graphene (BLG) and mercury cadmium telluride (MCT)-based single- and dual-junction photodetectors, namely, p(+)-BLG/n(-)-MCT and p(+)-BLG/n(-)-MCT/n(+)-MCT, operating in long infrared regime. The optoelectronic characterizations utilizing Silvaco Atlas TCAD are validated by analytical modeling. All the devices demonstrate self-powered mode operation and exhibit more than 10(6) times enhancement in photocurrent density. The dual-heterojunction photodetector demonstrates rapid photocurrent switching with the rise and fall time of similar to 0.05 and similar to 0.013 ps, respectively, than that of single-heterojunction-based photodetectors. The highest external quantum efficiency (QE(ext)), external photocurrent responsivity, and lowest noise equivalent power of 85.8%, 7.33 A/W, and 4.72x10(-20) W, respectively, are found for the dual-heterojunction photodetector with a wavelength of 10.6 mu m at 77 K. Such optimum photodetection performance is attributed to the presence of a huge amount of electric field (180 kV/cm) at n(-)-n(+) heterojunction, which accelerates the photogenerated electrons resulting in effective photocurrent. It is further demonstrated that the temperature-dependent QE(ext) with values >100% is due to the carrier multiplication effect in BLG.
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