KR101290150B1 - Semiconductor Lighting Device with a High Efficiency - Google Patents

Semiconductor Lighting Device with a High Efficiency Download PDF

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KR101290150B1
KR101290150B1 KR20090111652A KR20090111652A KR101290150B1 KR 101290150 B1 KR101290150 B1 KR 101290150B1 KR 20090111652 A KR20090111652 A KR 20090111652A KR 20090111652 A KR20090111652 A KR 20090111652A KR 101290150 B1 KR101290150 B1 KR 101290150B1
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South Korea
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light emitting
layer
emitting device
thin film
semiconductor light
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KR20090111652A
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Korean (ko)
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KR20110054859A (en
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허철
김경현
고현성
김봉규
김완중
홍종철
성건용
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한국전자통신연구원
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Abstract

The present invention relates to a high efficiency semiconductor light emitting device, wherein the semiconductor light emitting device according to the present invention comprises a lower electrode, a light emitting layer, and an upper electrode, wherein the light emitting layer includes silicon nanocrystals and is disposed on the light emitting layer. And a doped layer having a multilayer structure in which thin films having different band gaps are alternately grown. As the doping layer having a multi-layer structure in which thin films having different band gaps are alternately grown is included in the upper part of the light emitting layer, the carrier injection efficiency into the light emitting layer is increased, thereby ultimately increasing the light emitting efficiency.
Emission, Element, Efficiency, Bandgap

Description

Semiconductor Lighting Device with a High Efficiency

The present invention relates to a high efficiency semiconductor light emitting device. More particularly, the present invention relates to a semiconductor light emitting device in which light emission efficiency is increased by forming a transparent doped layer having a multi-layered structure having a different band gap on top of a light emitting layer including silicon nanocrystals.

In general, a semiconductor light emitting device is manufactured using a compound semiconductor thin film of gallium arsenide (GaAs) and gallium nitride (GaN). When manufacturing a light emitting device using a gallium arsenide-based gallium nitride-based compound semiconductor thin film, it is difficult to grow a high quality compound semiconductor thin film on a substrate, and the price of a compound semiconductor thin film such as sapphire, etc. The cost of equipment and gas sources for growth is high. Therefore, the conventional semiconductor light emitting device has a disadvantage of high manufacturing cost.

In addition, since the compound semiconductor thin film used for manufacturing a conventional semiconductor light emitting device is mainly grown on a non-silicon-based substrate, the conventional semiconductor light emitting device has a lot of difficulties in terms of integration or bonding with a silicon electronic device, so that mass production and Many disadvantages exist in the manufacture of low cost light emitting devices.

Therefore, in order to overcome the drawbacks as described above, a research on a method of manufacturing a semiconductor light emitting device using silicon has been actively conducted in recent years. Bulk silicon is known to be unable to fabricate light emitting devices because it has a physically indirect transition band structure. However, it is known that if the silicon has a nano size, the band structure has a shape of a direct transition band structure such as the band structure of the compound semiconductor in the indirect transition type structure, thereby producing a light emitting device that emits light.

In general, a method of manufacturing a silicon light emitting device uses a method of forming a light emitting layer for generating light by forming silicon nanocrystals in a silicon oxide film (SiOx). However, when the light emitting layer including the silicon nanocrystals is formed using a silicon oxide film, the manufacturing process is complicated because the silicon nanocrystals are formed by heat treatment at a high temperature of 1000 ° C. or higher, and the defects between the interface between the silicon oxide film and the silicon nanocrystals are complicated. It has a disadvantage in that it is difficult to control the wavelength of the light generated from the light emitting layer due to its presence.

Therefore, in order to overcome such drawbacks, researches using a silicon nitride (SiNx) thin film as a light emitting layer including silicon nanocrystals instead of a silicon oxide film have recently been conducted. When the silicon nitride thin film is used as a light emitting layer, silicon nanocrystals can be simultaneously formed in the thin film according to the mixing ratio of the source gas used for growing the thin film. Therefore, unlike the case where the silicon oxide film is used, It has the advantage that no heat treatment is required. In addition, since the silicon nitride thin film has a smaller band gap than the silicon oxide thin film, it is easy to inject carriers into the light emitting layer from the doping layer on the top of the light emitting layer, and there is less defect in the interface between the silicon nitride thin film and the silicon nanocrystal. It has the advantage that it is easy to control the wavelength of light generated from the light emitting layer.

As described above, many studies have been conducted because light emitting devices using silicon nanocrystals have many advantages over conventional compound semiconductor light emitting devices, but until now, light emitting efficiency is lower than that of compound semiconductor light emitting devices. Have Therefore, in order to improve the efficiency of the light emitting device using the silicon nanocrystals, it is essential to manufacture a light emitting layer structure having excellent light emitting efficiency, a transparent doping layer having excellent characteristics of carrier injection efficiency into the light emitting layer, and the like.

Therefore, the inventors of the present invention while researching a method for improving the efficiency of the silicon nano-crystal light emitting device, by manufacturing a doped layer of a multi-layer structure having a different band gap on the light emitting layer of the light emitting device from the upper doping layer to the light emitting layer The present invention has been accomplished by discovering that carrier injection efficiency can be improved.

Accordingly, an aspect of the present invention is to provide a semiconductor light emitting device having improved luminous efficiency by introducing a doping layer having a multi-layered structure having a different band gap to a light emitting device including silicon nanocrystals.

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In order to solve the above technical problem, the present invention is a semiconductor light emitting device comprising a lower electrode, a light emitting layer and an upper electrode, the light emitting layer includes silicon nanocrystals, alternate thin film having a different band gap on the light emitting layer It provides a semiconductor light emitting device comprising a doped layer of a multi-layer structure grown by.

The semiconductor light emitting device according to the present invention may further include a hole injection layer between the lower electrode and the light emitting layer, and may further include an electron injection layer or a transparent conductive electrode on the doping layer.

In the semiconductor light emitting device according to the present invention, the light emitting layer is a silicon nitride (SiNx) thin film containing silicon nanocrystals, and preferably has a thickness of 1 nm or more.

In the semiconductor light emitting device according to the present invention, a thin film having a different band gap constituting the doping layer is a thin film having a high band gap and a thin film having a low band gap are alternately grown, and the thin film having a high band gap. The silver silicon carbon nitride thin film is preferably a thin film having a low band gap is a silicon carbide thin film. In addition, one thickness of the thin film having different band gaps is preferably 1 nm or more, and the total thickness of the doping layer is preferably 1 μm or less, and the doping layer is preferably a transparent layer.

In the semiconductor light emitting device according to the present invention, a p-type silicon substrate may be used as the hole injection layer.

In addition, in the semiconductor light emitting device according to the present invention, the electron injection layer uses an n-type silicon carbide-based material, and preferably has a thickness of 1 nm or more, and the n-type silicon carbide-based material is SiC or It is preferable that it is SiCN, and the transparent conductive electrode includes ITO, SnO 2 , In 2 O 3 , Cd 2 SnO 4, or ZnO, and preferably has a thickness of 1 nm or more.

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In the semiconductor light emitting device according to the present invention, a doping layer having a multilayer structure formed by alternately growing a thin film having a large bandgap and a thin bandgap is formed on the light emitting layer to increase the carry injection efficiency into the light emitting layer, and consequently, silicon nano. The luminous efficiency of a crystal light emitting element can be improved.

Hereinafter, the present invention will be described in more detail with reference to the drawings. However, the embodiments of the present invention illustrated in the following may be modified in many different forms, and the scope of the present invention is not limited to the embodiments described below, but may be implemented in various different forms. In addition, embodiments of the present invention is provided to more fully describe the present invention to those skilled in the art, the size or thickness of the thin films in the drawings are exaggerated for clarity of specification.

2 is a cross-sectional view showing a semiconductor light emitting device according to an embodiment of the present invention, Figure 3 is a cross-sectional view showing a semiconductor light emitting device according to another embodiment of the present invention.

2 and 3, in the semiconductor light emitting device according to the present invention, a light emitting layer 110 formed on the hole injection layer 100 and thin films having different band gaps formed on the light emitting layer 110 are alternately stacked. The doped layer 200, the electron injection layer 120 formed on the doped layer 200, the transparent conductive electrode 130 and the upper hole injection layer 100 formed on the electron injection layer 120, and the The lower and upper electrodes 140 are disposed on the transparent conductive electrode 130.

The hole injection layer 100, the electron injection layer 120, and the transparent conductive electrode 130 may be formed using those commonly used in the art. In addition, the light emitting device according to the present invention may include a lower electrode / light emitting layer. In the simple structure of the doping layer / upper electrode, not only the structure of the lower electrode / hole injection layer / light emitting layer / doping layer / electron injection layer / transparent conductive electrode / upper electrode, but also the hole transport layer, hole suppression layer or electron A transport layer and the like may further be included.

A p-type silicon substrate may be used as the hole injection layer 100.

In addition, as the light emitting layer 110, a silicon nitride (SiNx) film containing silicon nanocrystals is used, and the thickness may be formed to be 1 nm or more, and preferably in the range of 1 nm or more to 1 μm or less. It is preferably formed. The silicon nanocrystals refer to silicon particles having a particle size of 1 nm to 10 nm. The silicon nanocrystals are formed in a silicon nitride thin film using plasma enhanced chemical vapor deposition.

The doped layer 200 formed on the light emitting layer 110 is a transparent layer in which thin films having different band gaps are alternately grown to form a multilayer structure. The thin film 200 having different band gaps may be formed by alternately growing the thin film 210 having the large band gap and the thin film 220 having the small band gap, and in this case, the difference in the band gap is within 0.1 to 2.0 eV. Is preferably. Specifically, a silicon carbon nitride thin film may be used as a thin band gap thin film, and a silicon carbide thin film may be used as a thin band gap thin film. The silicon carbon nitride thin film and the silicon carbide thin film layer may be continuously manufactured by changing the source gas.

The thickness of one thin film of the doped layer 200 forming the multilayer structure is preferably 1 nm or more, and the total thickness of the doped layer 200 preferably does not exceed 1 μm, for example, 1 nm. It is preferable that it is 1 micrometer or less in thickness above.

As the electron injection layer 120 formed on the doped layer 200, an n-type silicon carbide-based material may be used, and the thickness is preferably formed to be 1 nm or more, more preferably in the range of 1 μm or less. It is preferred to be formed within. For example, the silicon carbide-based material may be SiC, SiCN and the like.

The transparent conductive electrode 130 formed on the electron injection layer 120 is formed of indium tin oxide (ITO), SnO 2 , In 2 O 3 , Cd 2 SnO 4 , ZnO, or the like, and has a thickness of 1 nm or more. It is preferable to, and it is preferable to form in the range of 1 micrometer or less more preferably.

Upper and lower electrodes 140 are respectively disposed on the upper portion of the transparent conductive electrode 130 and the lower portion of the hole injection layer 100. The upper and lower electrodes 140 are preferably conductive metals such as nickel (Ni) and gold (Au). Through the upper and lower electrodes 140, a current is injected into the transparent conductive electrode 130 and the hole injection layer 100, and thus electrons and holes are injected into the light emitting layer 110 to emit light. Form the device.

Structures other than the light emitting layer 110 and the doped layer 200 may be formed in the same manner as in the prior art, and all of the layers may be formed by conventional methods such as chemical vapor deposition or physical vapor deposition, such as chemical vapor deposition. Can be deposited.

The semiconductor light emitting device manufactured as described above may be used for an optical biosensor.

Example

A light emitting layer was formed to a thickness of 50 nm using silicon nitride containing silicon nanocrystals on a p-type silicon substrate as a hole injection layer. Subsequently, a thin silicon carbon nitride thin film was formed on the light emitting layer with a thickness of 3 nm, and a thin silicon carbide thin film was formed on the light emitting layer with a thickness of 3 nm to prepare a doped layer having a multilayer structure. Subsequently, an electron injection layer was formed to a thickness of 40 nm using n-type silicon carbide on the doped layer. Subsequently, a transparent conductive electrode was formed to have a thickness of 100 nm with ITO, and an electrode was formed of Ni on the lower portion of the hole injection layer and on the transparent conductive electrode to fabricate a semiconductor light emitting device. Each of these layers was deposited using chemical vapor deposition.

Comparative example

A semiconductor light emitting device was manufactured in the same manner as in Example 1, except that the upper doped layer was not formed. Comparative Example Another light emitting device cross-sectional structure is the same as that of FIG.

Test Example

Evaluation of light emission characteristics of semiconductor light emitting device

Voltage vs. electroluminescence efficiency was evaluated for the light emitting devices obtained in Examples and Comparative Examples, and the results are shown in FIG. 4.

According to FIG. 4, it can be seen that the electroluminescence efficiency of the light emitting device including the doped layer having the multilayer structure is superior to the electroluminescent efficiency of the light emitting device not including the doped layer. This is because in the multilayer structure consisting of a silicon carbon nitride thin film having a large band gap and a silicon carbide thin film having a small band gap, electrons are collected in a silicon carbide region having a small band gap due to the discontinuity of the band gap, and thus when a voltage is applied to the light emitting device. The upper portion of the multi-layered structure of the silicon carbon nitride thin film having a larger band gap and the silicon carbide thin film having a smaller band gap than the structure including only the electron injection layer made of a silicon carbide thin film has an electron injection efficiency into a light emitting layer containing silicon nanocrystals This is because the electron injection efficiency is excellent in the structure including the doping layer.

1 is a cross-sectional view showing a conventional semiconductor light emitting device.

2 is a cross-sectional view illustrating a semiconductor light emitting device according to an embodiment of the present invention.

3 is a cross-sectional view illustrating a semiconductor light emitting device according to another embodiment of the present invention.

4 is a graph showing the results of comparing the luminous efficiency of the semiconductor light emitting device according to an embodiment of the present invention with the prior art.

Claims (13)

  1. In the semiconductor light emitting device comprising a lower electrode, a light emitting layer and an upper electrode,
    The light emitting layer includes silicon nano crystals,
    It includes a doped layer of a multi-layer structure in which the thin film having a different band gap on the light emitting layer alternately grown,
    The thin film having a different band gap is a semiconductor light emitting device, characterized in that the silicon carbide thin film having a high band gap and the silicon carbide thin film having a low band gap are alternately grown.
  2. The method of claim 1,
    And a hole injection layer between the lower electrode and the light emitting layer.
  3. The method of claim 1,
    The semiconductor light emitting device further comprises an electron injection layer or a transparent conductive electrode on the doped layer.
  4. The method according to any one of claims 1 to 3,
    The light emitting layer is a silicon nitride (SiNx) thin film containing silicon nanocrystals, and has a thickness of 1nm or more.
  5. delete
  6. delete
  7. The method according to any one of claims 1 to 3,
    The thickness of one of the thin films having different band gaps is 1 nm or more, and the total thickness of the doped layer is 1 μm or less.
  8. 3. The method of claim 2,
    A p-type silicon substrate is used as the hole injection layer.
  9. The method of claim 3,
    The electron injection layer uses an n-type silicon carbide-based material, and has a thickness of 1nm or more semiconductor light emitting device.
  10. 10. The method of claim 9,
    The n-type silicon carbide-based material is a semiconductor light emitting device, characterized in that SiC or SiCN.
  11. The method of claim 3,
    The transparent conductive electrode includes ITO, SnO 2 , In 2 O 3 , Cd 2 SnO 4 or ZnO, the semiconductor light emitting device, characterized in that having a thickness of 1nm or more.
  12. The method according to any one of claims 1 to 3,
    The doped layer is a semiconductor light emitting device, characterized in that the transparent layer.
  13. delete
KR20090111652A 2009-11-18 2009-11-18 Semiconductor Lighting Device with a High Efficiency KR101290150B1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20050099739A (en) * 2004-04-12 2005-10-17 한국전자통신연구원 Silicon light emitting device and method of manufacturing the same
KR20060132013A (en) * 1998-03-12 2006-12-20 니치아 카가쿠 고교 가부시키가이샤 Nitride semiconductor device
KR20070083377A (en) * 2006-02-21 2007-08-24 한국전자통신연구원 Transparent contact electrode for si nanocrystal light-emitting diodes, and method of fabricating

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060132013A (en) * 1998-03-12 2006-12-20 니치아 카가쿠 고교 가부시키가이샤 Nitride semiconductor device
KR20050099739A (en) * 2004-04-12 2005-10-17 한국전자통신연구원 Silicon light emitting device and method of manufacturing the same
KR20070083377A (en) * 2006-02-21 2007-08-24 한국전자통신연구원 Transparent contact electrode for si nanocrystal light-emitting diodes, and method of fabricating

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