On the Optoelectronic Mechanisms Ruling Ti-hyperdoped Si Photodiodes

Authors would like to acknowledge the technical and human support provided by Facility of Analysis and Characterization of Solids and Surfaces of SAIUEx (financed by UEX, Junta de Extremadura, MICINN, FEDER and FSE), as well as the CAI de Técnicas Físicas of the Universidad Complutense de Madrid for the ion implantation and rapid thermal annealing processes, and the ICTS Centro Nacional de Microscopia Electrónica for the microstructural measurements. The authors would like to thank Sven Kayser from IONTOF GmbH (Germany) for his helpful discussion about the dual beam configuration and ion beam mixing artefact. This work was partially supported by the Project MADRID-PV2 (P2018/EMT-4308) funded by the Regional Government of Madrid with the support from the European Regional Development Fund (ERDF), by the Spanish MINECO (Ministerio de Economía y Competitividad) under grants TEC2017-84378-R, PID2020-116508RB-I00, and PID2020-117498RB-I00. Daniel Caudevilla would also acknowledge the grant PRE2018-083798, financed by MICINN and European Social Fund. The authors are also thankful for financial collaboration from the Mexican grants program CONACyT.
This work deepens the understanding of the optoelectronic mechanisms ruling hyperdoped-based photodevices and shows the potential of Ti hyperdoped-Si as a fully complementary metal-oxide semiconductor compatible material for room-temperature infrared photodetection technologies. By the combination of ion implantation and laser-based methods, approximate to 20 nm thin hyperdoped single-crystal Si layers with a Ti concentration as high as 10(20) cm(-3) are obtained. The Ti hyperdoped Si/p-Si photodiode shows a room temperature rectification factor at +/- 1 V of 509. Analysis of the temperature-dependent current-voltage characteristics shows that the transport is dominated by two mechanisms: a tunnel mechanism at low bias and a recombination process in the space charge region at high bias. A room-temperature sub-bandgap external quantum efficiency (EQE) extending to 2.5 mu m wavelength is obtained. Temperature-dependent spectral photoresponse behavior reveals an increase of the EQE as the temperature decreases, showing a low-energy photoresponse edge at 0.45 eV and a high-energy photoresponse edge at 0.67 eV. Temperature behavior of the open-circuit voltage correlates with the high-energy photoresponse edge. A model is proposed to relate the optoelectronic mechanisms to sub-bandgap optical transitions involving an impurity band. This model is supported by numerical semiconductor device simulations using the SCAPS software.
MADRID-PV2 - Regional Government of Madrid
European Regional Development Fund (ERDF)
Ministerio de Economía y Competitividad (MINECO)
MICINN
European Social Fund
CONACyT
UEX
Junta de Extremadura
FEDER
FSE
Depto. de Estructura de la Materia, Física Térmica y Electrónica
Fac. de Ciencias Físicas
TRUE
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