• Title/Summary/Keyword: Photoresponse

Search Result 74, Processing Time 0.026 seconds

MoOx/Si Heterojunction for High-Performing Photodetector (MoOx 기반 실리콘 이종접합 고성능 광검출기)

  • Park, Wang-Hee;Kim, Joondong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.29 no.11
    • /
    • pp.720-724
    • /
    • 2016
  • Transparent n-type metal-oxide semiconductor of $MoO_x$ was applied on a p-type Si substrate for high-performing heterojunction photodetector. The formation of $MoO_x$ on Si spontaneously established a rectifying current flow with a high rectification ratio of 1,252.3%. Under light illumination condition, n-type $MoO_x$/p-type Si heterojunction device provided significantly fast responses (rise time : 61.28 ms, fall time : 66.26 ms). This transparent metal-oxide layer ($MoO_x$) would provide a functional route for various photoelectric devices, including photodetectors and solar cells.

Ultraviolet and visible light detection characteristics of amorphous indium gallium zinc oxide thin film transistor for photodetector applications

  • Chang, Seong-Pil;Ju, Byeong-Kwon
    • International journal of advanced smart convergence
    • /
    • v.1 no.1
    • /
    • pp.61-64
    • /
    • 2012
  • The ultraviolet and visible light responsive properties of the amorphous indium gallium zinc oxide thin film transistor have been investigated. Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor operate in the enhancement mode with saturation mobility of $6.99cm^2/Vs$, threshold voltage of 13.5 V, subthreshold slope of 1.58 V/dec and an on/off current ratio of $2.45{\times}10^8$. The transistor was subsequently characterized in respect of visible light and UV illuminations in order to investigate its potential for possible use as a detector. The performance of the transistor is indicates a high-photosensitivity in the off-state with a ratio of photocurrent to dark current of $5.74{\times}10^2$. The obtained results reveal that the amorphous indium gallium zinc oxide thin film transistor can be used to fabricate UV photodetector operating in the 366 nm.

Photoelectrochemical Converision with $SrTiO_3$ Ceramic Electrodes ($SrTiO_3$ 세라믹 전극에 의한 광전기 화학변환)

  • 윤기현;김태희
    • Journal of the Korean Ceramic Society
    • /
    • v.22 no.3
    • /
    • pp.19-24
    • /
    • 1985
  • The phtoelectrochemical porperties of $Nb_2O_5$, $Sb_2O_3$ and $V_2O_5$ doped and pure $SrTiO_3$ ceramic electodes were investigated. Shapes of I-V and I-λ characteristics of the pure $SrTiO_3$ ceramic electrode are similar to those of SrTiO3 single crystal electorde ; the anodic current strats at -0.9V (vs. Ag/AgCI) in 1 N-NaOH aqueous solution and the photoresponse appears at a wavelength of about 390nm and the quantum efficiency is about 3.5% at wavelength of 390nm under 0.5V vs. Ag/AgCl. Photocurrents of $Nb_2O_5$, $Sb_2O_3$ and $V_2O_5$ doped electrodes and $V_2O_5$ doped ceramic electrode appears at wavelength of 390nm and 500nm respectively.

  • PDF

A study on the characterization of properties and stabilities of a solar cell using diamond-like carbon/silicon heterojunctions (다이어몬드상 탄소/실리콘 이종접합 태양전지의 특성 및 신뢰성 분석에 관한 연구)

  • Park, Jin-Seok
    • Proceedings of the KIEE Conference
    • /
    • 1997.11a
    • /
    • pp.683-687
    • /
    • 1997
  • The purpose of this work is to develop a highly reliable solar cell based on the diamond-like carbon(DLC)/silicon heterojunction. Thin films of DLC have been deposited by employing both filtered cathodic vacuum arc(FCVA) and magnetron plasma-enhanced chemical vapor deposition(m-PECVD) systems. Structural, electrical, and optical properties of DLC films deposited are systematically analyzed as a function of deposition conditions, such as magnetic field, substrate bias voltage, gas pressure, and nitrogen content. The I-V measurement has been used to elucidate the mechanism responsible for the conduction process in the DLC/Si junction. Photoresponse characteristics of the junction are measured and its reliability against temperature and light stresses is also analyzed.

  • PDF

Graphite상의 ZnO Nanorod성장과 그를 이용한 Schottky Diode 제작

  • Nam, Gwang-Hui;Baek, Seong-Ho;Park, Il-Gyu
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2014.02a
    • /
    • pp.421.2-421.2
    • /
    • 2014
  • We report on the growth of ZnO nanorods (NRs) grown on graphite and silicon substrates via an all-solution process and characteristics of their heterojunctions. Structural investigations indicated that morphological and crystalline properties were not significantly different for the ZnO NRs on both substrates. However, optical properties from photoluminescence spectra showed that the ZnO NRs on graphite substrate contained more point defects than that on Si substrate. The ZnO NRs on both substrates showed typical rectification properties exhibiting successful diode formation. The heterojunction between the ZnO NRs and the graphite substrate showed a Schottky diode characteristic and photoresponse under ultraviolet illumination at a small reverse bias of -0.1 V. The results showed that the graphite substrate could be a good candidate for a Schottky contact electrode as well as a conducting substrate for electronic and optoelectronic applications of ZnO NRs.

  • PDF

Photovoltaic effect in $\beta$-carotene glass ($\beta$-carotene glass의 광기전력효과)

  • 김의훈
    • 전기의세계
    • /
    • v.20 no.4
    • /
    • pp.23-30
    • /
    • 1971
  • The photovoltaic behaviors ahve been observed with a sandwich-type cell, consisting of a junction between .betha.-carotene and stannic oxide conducting layer to provide a junction electrode. In the stannic oxide and .betha.-carotene junction it was found that its electromotive forse decreased to a value smaller than the original one. This is due to a space charge formation. Photovoltage reached approximately 40mV with an irradiation energy of 250Kcal/M$^{2}$hr. It appeared that a magnitude of the photovoltaic response was proportional to the logarithm of irradiance. The time constant of the photovoltaic effect was shown to be approximately 0.7 sec. The wavelength dependence of the photovoltaic behavior was very anomalous. It is assumed that such an anomalous photoresponse depends on a internal capacitance due to some bubble during process to make a cell.

  • PDF

MoS2 Thickness-Modulated MoS2/p-Si Photodetector (MoS2 두께 변화에 따른 MoS2/p-Si 광센서 특성 연구)

  • Kim, Hong-Sik;Kim, Joondong
    • Current Photovoltaic Research
    • /
    • v.5 no.4
    • /
    • pp.145-149
    • /
    • 2017
  • Transition metal dichalcogenides (TMDs) have attracted much attention because of their excellent optical and electrical properties, which are the applications of next generation photoelectric devices. In this study, $MoS_2$, which is a representative material of TMDs, was formed by magnetic sputtering method and surface changes and optical characteristics were changed with thickness variation. In addition, by implementing the photodetector of $MoS_2/p-Si$ structure, it was confirmed that the change of the electrical properties rather than the change of the optical properties according to the thickness change of $MoS_2$ affects the photoresponse ratio of the photodetector. This result can be used to fabricate effective photoelectric devices using $MoS_2$.

Influence of Grain Size and Dopant ZnO on the Photoelectrochemical Conversion in TiO2 Ceramic Electrods (TiO2 세라믹 전극의 광전기 화학 변환에 미치는 결정립 크기와 첨가제 ZnO의 영향)

  • 윤기현;장병규;김태희
    • Journal of the Korean Ceramic Society
    • /
    • v.26 no.2
    • /
    • pp.258-266
    • /
    • 1989
  • The effects of grain size and dopant ZnO on the photoelectrochemical conversion in TiO2 ceramic electrodes have been investigated. The photocurrent increases with increasing grain size in the undoped TiO2 ceramic electrode. In ZnO-doped TiO2 electrodes, the photocurrent decreases with increasing ZnO up to 0.4 wt% due to decrease of donor concentration, and then with further addition of ZnO, photocurrent increases according to the formation of second phase. However, the photoresponse appears at wavelength of 420nm, which is very close to the energy band gap of TiO2, regardless of grain size and amount of ZnO.

  • PDF

Ultraviolet Photodetection Properties of ZnO/Si Heterojunction Diodes Fabricated by ALD Technique Without Using a Buffer Layer

  • Hazra, Purnima;Singh, S.K.;Jit, S.
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.14 no.1
    • /
    • pp.117-123
    • /
    • 2014
  • The fabrication and characterization of a Si/ZnO thin film heterojunction ultraviolet photodiode has been presented in this paper. ZnO thin film of ~100 nm thick was deposited on <100> Silicon (Si) wafer by atomic layer deposition (ALD) technique. The Photoluminescence spectroscopy confirms that as-deposited ZnO thin film has excellent visible-blind UV response with almost no defects in the visible region. The room temperature current-voltage characteristics of the n-ZnO thin film/p-Si photodiodes are measured under an UV illumination of $650{\mu}W$ at 365 nm in the applied voltage range of ${\pm}2V$. The current-voltage characteristics demonstrate an excellent UV photoresponse of the device in its reverse bias operation with a contrast ratio of ~ 1115 and responsivity of ~0.075 A/W at 2 V reverse bias voltage.

GaN-based Ultraviolet Passive Pixel Sensor for UV Imager

  • Lee, Chang-Ju;Hahm, Sung-Ho;Park, Hongsik
    • Journal of Sensor Science and Technology
    • /
    • v.28 no.3
    • /
    • pp.152-156
    • /
    • 2019
  • An ultraviolet (UV) image sensor is an extremely important optoelectronic device used in scientific and medical applications because it can detect images that cannot be obtained using visible or infrared image sensors. Because photodetectors and transistors are based on different materials, conventional UV imaging devices, which have a hybrid-type structure, require additional complex processes such as a backside etching of a GaN epi-wafer and a wafer-to-wafer bonding for the fabrication of the image sensors. In this study, we developed a monolithic GaN UV passive pixel sensor (PPS) by integrating a GaN-based Schottky-barrier type transistor and a GaN UV photodetector on a wafer. Both individual devices show good electrical and photoresponse characteristics, and the fabricated UV PPS was successfully operated under UV irradiation conditions with a high on/off extinction ratio of as high as $10^3$. This integration technique of a single pixel sensor will be a breakthrough for the development of GaN-based optoelectronic integrated circuits.