title: Boosting photoresponse in silicon metal-semiconductor-metal photodetector using semiconducting quantum dots.
abstract: Silicon based metal-semiconductor-metal (MSM) photodetectors have faster photogeneration and carrier collection across the metal-semiconductor Schottky contacts, and CMOS integratibility compared to conventional p-n junction photodetectors. However, its operations are limited by low photogeneration, inefficient carrier-separation, and low mobility. Here, we show a simple and highly effective approach for boosting Si MSM photodetector efficiency by uniformly decorating semiconducting CdSe quantum dots on Si channel (Si-QD). Significantly higher photocurrent on/off ratio was achieved up to over 500 compared to conventional Si MSM photodetector (on/off ratio ~5) by increasing photogeneration and improving carrier separation. Furthermore, a substrate-biasing technique invoked wide range of tunable photocurrent on/off ratio in Si-QD photodetector (ranging from 2.7 to 562) by applying suitable combinations of source-drain and substrate biasing conditions. Strong photogeneration and carrier separation were achieved by employing Stark effect into the Si-QD hybrid system. These results highlight a promising method for enhancing Si MSM photodetector efficiency more than 100 times and simultaneously compatible with current silicon technologies.
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea.|Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea.|Electrical and Computer Engineering, University of Texas at El Paso, El Paso, TX 79968, USA.
authors.forename: Chandan
authors.initials: C
authors.lastname: Biswas
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea.|Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
authors.forename: Yonghwan
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea.|Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee
mesh_terms: D004867:Equipment Design; D055096:Optical Devices; D045663:Quantum Dots / Q000737:chemistry*; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry*
chemical_list: D012825:Silicon