Ultraviolet and visible photoresponse properties of n-ZnO/p-Si heterojunction

Journal Article · Sun Apr 15 04:00:00 EDT 2007 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2724808· OSTI ID:20982811

Mridha, S; Basak, D ^[1]

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1. Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

A n-ZnO/p-Si thin film heterojunction has been fabricated by a low cost sol-gel technique. The wavelength dependent photoresponse properties of the heterojunction is investigated in detail by studying the effect of light illumination on current-voltage (I-V) characteristics, photocurrent, and photocapacitance spectra at room temperature. It shows good diode characteristics with I{sub F}/I{sub R}=3.4x10{sup 3} at 4 V and reverse leakage current density of 7.6x10{sup -5} A cm{sup -2} at -5 V. From the photocurrent spectra, it is observed that the visible photons are absorbed in the depleted p-Si under reverse bias conditions, while ultraviolet (UV) photons are absorbed in the depleted n-ZnO under positive bias conditions. This indicates that such a sol-gel n-ZnO/p-Si thin film heterojunction can be used to sense both UV and visible photons though the photoresponse for UV is much slower than that of visible. The photocapacitance measurements suggest the presence of a shallow defect level in the sol-gel derived ZnO film which acts as an electron trap at {approx}0.16 eV below the conduction band.

• OSTI ID: 20982811
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 101; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CURRENT DENSITY
ELECTRIC POTENTIAL
ELECTRONS
HETEROJUNCTIONS
LEAKAGE CURRENT
PHOTOCONDUCTIVITY
PHOTONS
SEMICONDUCTOR MATERIALS
SILICON
SOL-GEL PROCESS
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
ULTRAVIOLET RADIATION
VISIBLE RADIATION
ZINC OXIDES