Electrical and optical properties of InP nanowire ensemble pâº-i-n⺠photodetectors.
Nanotechnology
; 23(13): 135201, 2012 Apr 06.
Article
em En
| MEDLINE
| ID: mdl-22418741
ABSTRACT
We report on a comprehensive study of electrical and optical properties of efficient near-infrared pâº-i-n⺠photodetectors based on large ensembles of self-assembled, vertically aligned i-n⺠InP nanowires monolithically grown on a common p⺠InP substrate without any buffer layer. The nanowires have a polytype modulated crystal structure of wurtzite and zinc blende. The electrical data display excellent rectifying behavior with an ideality factor of about 2.5 at 300 K. The ideality factor scales with 1/T, which possibly reflects deviations from classical transport models due to the mixed crystal phase of the nanowires. The observed dark leakage current is of the order of merely â¼100 fA/nanowire at 1 V reverse bias. The detectors display a linear increase of the photocurrent with reverse bias up to about 10 pA/nanowire at 5 V. From spectrally resolved measurements, we conclude that the photocurrent is primarily generated by funneling photogenerated carriers from the substrate into the NWs. Contributions from direct excitation of the NWs become increasingly important at low temperatures. The photocurrent decreases with temperature with an activation energy of about 50 meV, which we discuss in terms of a temperature-dependent diffusion length in the substrate and perturbed transport through the mixed-phase nanowires.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nanotechnology
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Suécia