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Nano Letters
Volumn 7, Issue 4, 2007, Pages 1003-1009
ZnO nanowire UV photodetectors with high internal gain
Author keywords

[No Author keywords available]
Indexed keywords

GAIN-BANDWIDTH PRODUCTS (GB); OXYGEN-RELATED HOLE-TRAP STATES; PHOTOCONDUCTIVE GAIN; ZNO NANOWIRE (NW);
EID: 34248140089     PISSN: 15306984     EISSN: None     Source Type: Journal    
DOI: 10.1021/nl070111x     Document Type: Article
Times cited : (2487)
References (48)
  • 24
    • 34248185873 scopus 로고    scopus 로고
    • I-V measurements in the dark and under illumination were obtained by applying an external bias to the NW and recorded using a low-noise current preamplifier (Ithaco 1211) in conjunction with a 100 kS/s, 16 bit digital acquisition board (National Intruments PCI-6030E, The time delay between acquisitions was set at t, 100 ms. A Hg arc discharge lamp was used as the excitation source, and monochromatric UV illumination was obtained by a dielectric bandpass filter centered at 390 nm (±50 nm) placed in front of the lamp. The optical power impinging on the nanowire photodetectors was varied by means of neutral density filters. The illumination intensity was determined by a thermopile detector (SpectraPhysics 407A, Measurements under vacuum were obtained by placing the samples in the vacuum chamber of a cold probe station MMR Technologies, Inc, at a pressure of P < 10 -4 Torr
    • -4 Torr.
  • 37
    • 30844470694 scopus 로고    scopus 로고
    • 2 and assumed 85% absorption of the incident power based on ∼10% surface reflection and ∼95% absorption in the ∼300 nm diameter NW at 3.5 eV (see Zhang, Z. H.; Qi, X. Y.; Jian, J. K.; Duan, X. F. Micron 2006, 37, 229-233).
    • 2 and assumed 85% absorption of the incident power based on ∼10% surface reflection and ∼95% absorption in the ∼300 nm diameter NW at 3.5 eV (see Zhang, Z. H.; Qi, X. Y.; Jian, J. K.; Duan, X. F. Micron 2006, 37, 229-233).
  • 41
    • 34248213980 scopus 로고    scopus 로고
    • The frequency and spectral dependence of the photocurrent were obtained using a conventional modulation technique, where the light emitted by a Xe arc discharge lamp, modulated by a mechanical chopper (EG&G-PAR 197, frequency range up to 3000 Hz, was used as the excitation source, in conjunction with a monochromator and a lock-in amplifier (Ithaco 3921 or Stanford Research SR520) for measuring the photocurrent. For determining the photocurrent spectra, the raw data were calibrated against the excitation intensity determined by means of a calibrated Si photodiode Newport 818-UV
    • The frequency and spectral dependence of the photocurrent were obtained using a conventional modulation technique, where the light emitted by a Xe arc discharge lamp, modulated by a mechanical chopper (EG&G-PAR 197, frequency range up to 3000 Hz), was used as the excitation source, in conjunction with a monochromator and a lock-in amplifier (Ithaco 3921 or Stanford Research SR520) for measuring the photocurrent. For determining the photocurrent spectra, the raw data were calibrated against the excitation intensity determined by means of a calibrated Si photodiode (Newport 818-UV).
  • 42
    • 34248230066 scopus 로고    scopus 로고
    • 2), but consistent with the extrapolation at zero frequency of the -20 dB/ decade line shown in Figure 4b. The deviation of the experimental data from the expected gain values at low modulation frequencies may be due to the presence of multiple time constants, which would result in multiple poles and zeros of the transfer function G(v).
    • 2), but consistent with the extrapolation at zero frequency of the -20 dB/ decade line shown in Figure 4b. The deviation of the experimental data from the expected gain values at low modulation frequencies may be due to the presence of multiple time constants, which would result in multiple poles and zeros of the transfer function G(v).
  • 45
    • 34248222486 scopus 로고    scopus 로고
    • -4 Torr.
    • -4 Torr.
  • 46
    • 34248199778 scopus 로고    scopus 로고
    • It is noteworthy that, due to the extremely high photon flux required to obtain a satisfactory signal-to-noise ratio in these measurements, the gain values that would correspond to the photocurrent transients in Figure 6a are well below unity, as expected from the gain saturation at such excitation intensities (I = 0.3 μJ/pulse).
    • It is noteworthy that, due to the extremely high photon flux required to obtain a satisfactory signal-to-noise ratio in these measurements, the gain values that would correspond to the photocurrent transients in Figure 6a are well below unity, as expected from the gain saturation at such excitation intensities (I = 0.3 μJ/pulse).

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.