• 제목/요약/키워드: n-Type semiconductor

검색결과 406건 처리시간 0.023초

Enhanced optical output power of AlGaN/GaN ultraviolet light-emitting diodes fabricated with breakdown induced conductive channels

  • Seonghoon Jeong;Sung-Nam Lee;Chel-Jong Choi;Hyunsoo Kim
    • Journal of Ceramic Processing Research
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    • 제21권
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    • pp.23-27
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    • 2020
  • The enhanced optical output power of AlGaN/GaN deep ultraviolet light-emitting diodes (UV LEDs) were demonstrated by using the breakdown-induced conductive channels (BICCs). The BICCs could be made by electrical reverse biasing between two adjacent contact pads formed on top p-type layers with a certain distance, causing an electrical breakdown of pn junction and hence a generation of conductive channels. Accordingly, the reflective Ni/Ag/Pt electrodes could be formed simultaneously on the top p-type layer and the other p-type layer with the BICCs, acting as the p- and n-contacts, respectively. The deep UV LEDs fabricated with the BICCs produced the enhanced optical output power by 15 % as compared to the reference LEDs, which were fabricated with the conventional Ti/Al/Ti/Au layers formed on mesa-etched n-type layer. This could be due to the reduced light absorption at the n-contact pads, indicating that the use of BICCs will be very suitable for obtaining better output performance of deep UV emitters.

분산된 p형 및 n형 반도체 입자의 도핑 효과와 반도체 동작 (Doping Effects and Semiconductor Behaviors of the Dispersed p- and n- type Semiconductor Particles)

  • 천장호;손광철;라극환;조은철
    • 전자공학회논문지A
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    • 제31A권5호
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    • pp.126-133
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    • 1994
  • Doping effects and semiconductor behaviors of the dispersed p- and n-Si, p- and n- GaAs particles in the aqueous electrolyte have been studied using microelectrophoretic, voltammetric and chronoamperometric techniques. The cations (K$^{+}$) are adsorbed on both the p- and n- Si particle surfaces regardless of the sign of space charges in the depletion layers, i.e. doping profiles. The surface states are negatively charged acceptor states. On the other hand, the anions (CI$^{-}$) are adsorbed on both the p- and n- GaAs particle surfaces regardless of the sign of space charges in the depletion layers, i.e. doping profiles. The surface states are positively charged donor states. Under the same conditions, electrophoretic mobilities, electrochemical processes, doping effects and related semiconductor behaviors of the Si and the GaAs particles are similar regardless of the doping profiles, i. e. dopants and doping concentrations. The doping effects and related semiconductor behaviors of the dispersed p- and n- type semiconductor particles are gradually lost with decreasing dimensions.

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Organic complementary inverter and ring oscillator on a flexible substrate

  • Kim, Min-Gyu;Cho, Hyun-Duck;Kwak, Jeong-Hun;Kang, Chan-Mo;Park, Myeong-Jin;Lee, Chang-Hee
    • Journal of Information Display
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    • 제12권1호
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    • pp.1-4
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    • 2011
  • A complementary inverter was fabricated using pentacene and N-N -dioctyl-3,4,9,10-perylene tetracarboxylic diimide-C (PTCDI-C8) for p- and n-type transistors on a poly(ether sulfone) substrate, respectively. The mobilities of the p- and n-type transistors were 0.056 and 0.013 $cm^2$/Vs, respectively. The inverter, which was composed of p- and n-type transistors, showed a gain of 48.6 when $V_{DD}$ = -40V and at the maximum noise margin of $V_{DD}$/2. A ring oscillator was also fabricated by cascading five inverters. The five-stage ring oscillator showed the maximum output frequency of 10 kHz when $V_{DD}$ = -170 V.

Detection of Streptavidin-Biotin Complexes Using a Highly Sensitive AlGaN/GaN-Based Extended-Gate MISHEMT-Type Biosensor

  • Lee, Hee Ho;Bae, Myunghan;Choi, Byoung-Soo;Shin, Jang-Kyoo
    • 센서학회지
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    • 제25권5호
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    • pp.320-325
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    • 2016
  • In this paper, we propose an AlGaN/GaN-based extended-gate metal-insulator-semiconductor high electron mobility transistor (MISHEMT)-type biosensor for detecting streptavidin-biotin complexes. We measure the drain current of the fabricated sensor, which varies depending on the antibody-antigen reaction of streptavidin with biotin molecules. To confirm the immobilization of biotin polyethylene glycol (PEG) thiol, we analyze the Au surface of a GaN sample using X-ray photoelectron spectroscopy (XPS). The proposed biosensor shows higher sensitivity than Si-based extended-gate metal oxide semiconductor field effect transistor (MOSFET)-type biosensor. In addition, the proposed AlGaN/GaN-based extended-gate MISHEMT-type biosensor exhibits better long-term stability, compared to the conventional AlGaN/GaN-based MISHEMT-type biosensor.

Effects of Current Spreading in GaN-based Light-emitting Diodes Using ITO Spreading Pad

  • Kim, Jang Hyun;Kim, Garam;Park, Euyhwan;Kang, Dong Hoon;Park, Byung-Gook
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제15권1호
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    • pp.114-121
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    • 2015
  • In conventional LEDs, a mesa-structure is usually used and it causes the current to be overcrowded in a specific region. We propose a novel structure of GaN-based LED to overcome this problem. In order to distribute the current in an active region, a spreading pad is inserted at the p-type region in the GaN based LED device. The inserted spreading pad helps the current flow because it is more conductive than the p-type GaN layer. By performing electrical and optical simulations, the effects of the spreading pad insertion are confirmed. The results of electrical simulation show that the current spreads more uniformly and more radiative recombination is produced as well. Moreover, from the optical simulation, it is revealed that the ITO is less absorptive material than p-GaN if the condition of specific wavelength sources is satisfied. Considering all of the results, we can conclude that the luminescent power is enhanced by the spreading pad.

Reduction of Current Crowding in InGaN-based Blue Light-Emitting Diodes by Modifying Metal Contact Geometry

  • Kim, Garam;Kim, Jang Hyun;Park, Euyhwan;Park, Byung-Gook
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제14권5호
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    • pp.588-593
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    • 2014
  • Current crowding problem can worsen the internal quantum efficiency and the negative-voltage ESD of InGaN-based LEDs. In this paper, by using photon emission microscope and thermal emission microscope measurement, we confirmed that the electric field and the current of the InGaN-based LED sample are crowded in specific regions where the distance between p-type metal contact and n-type metal contact is shorter than other regions. To improve this crowding problem of electric field and current, modified metal contact geometry having uniform distance between the two contacts is proposed and verified by a numerical simulation. It is confirmed that the proposed structure shows better current spreading, resulting in higher internal quantum efficiency and reduced reverse leakage current.

투명한 p형 반도체 CuAlO2 박막의 일산화질소 가스 감지 특성 (Nitrogen Monoxide Gas Sensing Characteristics of Transparent p-type Semiconductor CuAlO2 Thin Films)

  • 박수정;김효진;김도진
    • 한국재료학회지
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    • 제23권9호
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    • pp.477-482
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    • 2013
  • We investigated the detection properties of nitrogen monoxide (NO) gas using transparent p-type $CuAlO_2$ thin film gas sensors. The $CuAlO_2$ film was fabricated on an indium tin oxide (ITO)/glass substrate by pulsed laser deposition (PLD), and then the transparent p-type $CuAlO_2$ active layer was formed by annealing. Structural and optical characterizations revealed that the transparent p-type $CuAlO_2$ layer with a thickness of around 200 nm had a non-crystalline structure, showing a quite flat surface and a high transparency above 65 % in the range of visible light. From the NO gas sensing measurements, it was found that the transparent p-type $CuAlO_2$ thin film gas sensors exhibited the maximum sensitivity to NO gas in dry air at an operating temperature of $180^{\circ}C$. We also found that these $CuAlO_2$ thin film gas sensors showed reversible and reliable electrical resistance-response to NO gas in the operating temperature range. These results indicate that the transparent p-type semiconductor $CuAlO_2$ thin films are very promising for application as sensing materials for gas sensors, in particular, various types of transparent p-n junction gas sensors. Also, these transparent p-type semiconductor $CuAlO_2$ thin films could be combined with an n-type oxide semiconductor to fabricate p-n heterojunction oxide semiconductor gas sensors.

Temperature Dependent Current Transport Mechanism in Graphene/Germanium Schottky Barrier Diode

  • Khurelbaatar, Zagarzusem;Kil, Yeon-Ho;Shim, Kyu-Hwan;Cho, Hyunjin;Kim, Myung-Jong;Kim, Yong-Tae;Choi, Chel-Jong
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제15권1호
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    • pp.7-15
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    • 2015
  • We have investigated electrical properties of graphene/Ge Schottky barrier diode (SBD) fabricated on Ge film epitaxially grown on Si substrate. When decreasing temperature, barrier height decreased and ideality factor increased, implying their strong temperature dependency. From the conventional Richardson plot, Richardson constant was much less than the theoretical value for n-type Ge. Assuming Gaussian distribution of Schottky barrier height with mean Schottky barrier height and standard deviation, Richardson constant extracted from the modified Richardson plot was comparable to the theoretical value for n-type Ge. Thus, the abnormal temperature dependent Schottky behavior of graphene/Ge SBD could be associated with a considerable deviation from the ideal thermionic emission caused by Schottky barrier inhomogeneities.

Cr capping layer를 이용한 n-Ge(100) 기판에서의 Ti germanide 형성과 특성에 관한 연구 (The Formation and Characteristics of Titanium Germanide with Cr capping layer on n-Ge(100) Substrate)

  • 문란주;최철종;심규환
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.154-154
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    • 2009
  • Cr capping layer를 이용하여 Titanium germanide의 열적 안정성을 향상시키는 연구를 수행하였다. n-type Ge(100) 기판 위에 전자빔 증착기를 이용하여 30nm 두께의 Ti와 Cr capping layer를 증착하고 $400\;^{\circ}C$에서 $800\;^{\circ}C$까지 30초간 N2 분위기로 급속 열처리하여 Ti germanide를 형성하였다. XRD결과로부터 Cr capping layer의 유무에 관계 없이 Ti germanide가 형성된 것을 관찰할 수 있었다. Ge 기판 위에 CTLM 패턴을 형성하고 실험을 진행하여 Ti germanide의 I-V 측정 데이터를 통해 Ohmic 특성을 알아보았고, contact resistance, sheet resistance, specific contact resistance를 구하였다.

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기판의 종류에 따른 SnO2 박막의 전기적인 특성 연구 (Study on the Electrical Characteristics of SnO2 on p-Type and n-Type Si Substrates)

  • 오데레사
    • 반도체디스플레이기술학회지
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    • 제16권2호
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    • pp.9-14
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    • 2017
  • $ISnO_2$ thin films were prepared on p-type and n-type Si substrates to research the interface characteristics between $SnO_2$ and substrate. After the annealing processes, the amorphous structure was formed at the interface to make a Schottky contact. The O 1s spectra showed the bond of 530.4 eV as an amorphous structure, and the Schottky contact. The analysis by the deconvoluted spectra was observed the drastic variation of oxygen vacancies at the amorphous structure because of the depletion layer is directly related to the oxygen vacancy. $SnO_2$ thin film changed the electrical properties depending on the characteristics of substrates. It was confirmed that it is useful to observe the Schottky contact's properties by complementary using the XPS analysis and I-V measurement.

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