engleski

Hybrid nano-slicon/organic semiconductor junctions for NIR optoelectronics

Infrared sensitivity of the silicon photodiodes is limited by the 1.11 eV band-gap of bulk silicon. Hybrid junctions of silicon and matching organic semiconductor for photodiodes show promise in extending the range of spectral sensitivity of silicon. Extension of spectral sensitivity to infrared wavelengths beyond 1250 nm, while keeping the CMOS compatibility would be of great importance to possible telecom or other optoelectronic uses. By vacuum-deposition of thin films of organic semiconductors on silicon substrates it is possible to vary the barrier height of the heterojunction, and thus also the spectral response of the devices. By using micro and nano- structured silicon substrates, electronic and optical properties of structured substrates can be used to improve the device performance in comparison to using flat substrates. Heterojunction photodiodes based on thin films of hydrogen-bonded pigment tyrian purple (6, 6'- dibromoindigo) formed on silicon substrates by vacuum evaporation show sub silicon-bandgap IR sensitivity up to 2500 nm with responsivity of ~5 mA/W in the telecom C-band [1, 2]. We show how micro- and nano- structuring of silicon substrates prior to vacuum evaporation of organic layer significantly improves the responsivity of hybrid silicon-organic photodiodes. [1] M. Bednorz, G. J. Matt, E. D. Głowacki, T. Fromherz, C. J. Brabec, M. C. Scharber, H. Sitter, and N. S. Sariciftci, Org. Electron. 14 (2013), 1344 [2] V. Đerek, E. Głowacki, M. Sytnyk, W. Heiss, M. Marciuš, M. Ristić, M. Ivanda, and N.S. Sariciftci, Applied Physics Letters, 107 (2015) 083302

hybrid; organic; silicon; semiconductor; junction; NIR; photodiode

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