Materials, Photonic Devices, and Sensors

Improvement of external quantum efficiency of silicide Schottky-barrier detectors in the 3 to 5 μm waveband with subwavelength-grating incident plane

[+] Author Affiliations
Bingxin Kang, Yi Cai, Lingxue Wang

Beijing Institute of Technology, School of Optoelectronics, Key Laboratory of Photoelectronic Imaging Technology and Systems, 5th South Avenue of Zhongguan Village, Beijing 100081, China

Opt. Eng. 55(4), 047103 (Apr 06, 2016). doi:10.1117/1.OE.55.4.047103
History: Received December 1, 2015; Accepted March 8, 2016
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Abstract.  Silicide Schottky-barrier midwave infrared detectors for the 3 to 5  μm waveband typically use a 2 to 8 nm metal-silicide layer grown on silicon substrates as an absorption layer. We demonstrate the use of an SiO2-film-coated subwavelength grating as an antireflection incident plane in such detectors to enhance absorption at the 3 to 5  μm waveband in the metal-silicide layer for improving the external quantum efficiency (EQE). Taking a PtSi/p-Si structure as an example, we fabricate samples and build a test platform to characterize the EQE of a PtSi/p-Si Schottky-barrier detector. Simulation results show that low reflection efficiency (<9%) for the subwavelength-grating incident plane and factors of 1.5 to 1.8 enhancement in absorption of the PtSi layer are achieved at normal incidence across the 3 to 5  μm waveband. Measurement results show that this increase translates into factors of 1.3 to 1.7 enhancement in EQE. This improvement in EQE results from absorption enhancement due to antireflection effects and the forward scattering of incident infrared radiation in the subwavelength grating, which increases the effective optical path in the detector. The results also suggest that fabricating a subwavelength-grating incident plane is a general, low-cost method to enhance EQE in various infrared material platforms used for back-illuminated detectors.

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© 2016 Society of Photo-Optical Instrumentation Engineers

Citation

Bingxin Kang ; Yi Cai and Lingxue Wang
"Improvement of external quantum efficiency of silicide Schottky-barrier detectors in the 3 to 5 μm waveband with subwavelength-grating incident plane", Opt. Eng. 55(4), 047103 (Apr 06, 2016). ; http://dx.doi.org/10.1117/1.OE.55.4.047103


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