Article Title

Study of photocurrent generation in InP nanowire-based p⁺-i-n⁺ photodetectors

Authors

Vishal Jain, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University, Box 823, SE-301-18 Halmstad, Sweden
Ali Nowzari, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden
Jesper Wallentin, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden
Magnus T. Borgstrm, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden
Maria E. Messing, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden
Damir Asoli, Sol Voltaics AB, Ideon Science Park, Scheelevgen 17, SE-22370 Lund, Sweden
Mariusz Graczyk, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden
Bernd Witzigmann, Department of Computational Electronics and Photonics, University of Kassel, Wilhelmshoeher Allee 71, D-34121 Kassel, Germany
Federico Capasso, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
Lars Samuelson, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden
Hkan Pettersson, Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, SE-22100 Lund, Sweden Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University, Box 823, SE-301-18 Halmstad, Sweden

Keywords

nanophotonics, nanowires, infrared (IR), photodetectors, solar cells

Abstract

We report on electrical and optical properties of p+–i–n+ photodetectors/solar cells based on square millimeter arrays of InP nanowires (NWs) grown on InP substrates. The study includes a sample series where the p+-segment length was varied between 0 and 250 nm, as well as solar cells with 9.3% efficiency with similar design. The electrical data for all devices display clear rectifying behavior with an ideality factor between 1.8 and 2.5 at 300 K. From spectrally resolved photocurrent measurements, we conclude that the photocurrent generation process depends strongly on the p+-segment length. Without a p+-segment, photogenerated carriers funneled from the substrate into the NWs contribute strongly to the photocurrent. Adding a p+-segment decouples the substrate and shifts the depletion region, and collection of photogenerated carriers, to the NWs, in agreement with theoretical modeling. In optimized solar cells, clear spectral signatures of interband transitions in the zinc blende and wurtzite InP layers of the mixed-phase i-segments are observed. Complementary electroluminescence, transmission electron microscopy (TEM), as well as measurements of the dependence of the photocurrent on angle of incidence and polarization, support our interpretations.

Graphical Abstract

DOI

https://doi.org/10.1007/s12274-014-0422-2

Publisher

Tsinghua University Press

Recommended Citation

Vishal Jain,Ali Nowzari,Jesper Wallentin,Magnus T. Borgström,Maria E. Messing,Damir Asoli,Mariusz Graczyk,Bernd Witzigmann,Federico Capasso,Lars Samuelson,Håkan Pettersson, Study of photocurrent generation in InP nanowire-based p+-i-n+ photodetectors. NanoRes.2014, 7(4): 544–552