JP5420109B2 - Multiple solar cell having PN junction and Schottky junction and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solar cell, and more particularly to a multiple solar cell having a PN junction and a Schottky junction.

  Unlike other energy sources, solar cells, which are photoelectric conversion elements that convert sunlight into electrical energy, are infinite and environmentally friendly. Therefore, their importance increases over time.

  In particular, the high crude oil price and the limited nature of fossil fuels seem to increase the use of renewable energy, but among them, the dependence of solar cells that can be easily moved and carried is even greater. is expected.

  Briefly describing the structure and principle of the solar cell, the solar cell has a PN junction structure in which a P (positive) type semiconductor and an N (negative) type semiconductor are joined. When sunlight enters the solar cell having such a structure, holes and electrons are generated in the semiconductor by the energy of the incident sunlight. At this time, the hole (+) moves to the P-type semiconductor side by the electric field generated at the PN junction, and the electron (−) moves to the N-type semiconductor side to generate electric potential, thereby generating electric power. It is the principle of becoming.

  Such solar cells are classified into substrate type solar cells and thin film type solar cells. A substrate type solar cell is a solar cell manufactured using a semiconductor material itself such as silicon as a substrate. A thin film type solar cell is formed by forming a semiconductor in a thin film form on a substrate such as glass. A solar cell is manufactured.

  Substrate type solar cells are slightly more efficient than thin film type solar cells, but there is a limit to minimizing the thickness in the process, and manufacturing costs increase due to the use of expensive semiconductor substrates. There are disadvantages. Thin-film solar cells are slightly less efficient than substrate solar cells, but they can be manufactured in thin thicknesses and have the advantage of lower manufacturing costs because low-cost materials can be used. Suitable for mass production.

  However, even in the case of a substrate type solar cell and a thin film type solar cell, since one PN semiconductor forms one solar cell, the process is complicated, and in order to increase the voltage, the solar cells arranged side by side Have to be connected in series.

  An object of the present invention is to provide a multiple solar cell having a PN junction and a Schottky junction with improved efficiency.

  A solar cell according to an embodiment of the present invention includes a PN semiconductor layer in which a P-type semiconductor layer and an N-type semiconductor layer are stacked, a first electrode that is in ohmic contact with a first surface of the PN semiconductor layer, A Schottky junction layer that is Schottky-bonded to a second surface facing away from the first surface of the PN semiconductor layer; a second electrode that is formed so as to be in contact with the Schottky junction layer; and the Schottky junction layer; A recombination prevention layer is included as an insulating material between the PN semiconductor layer.

  The recombination prevention layer may be formed to have a thickness of 0.1 nm to 10 nm. The N-type semiconductor layer may be disposed so as to be in contact with the recombination preventing layer, and the Schottky junction layer may be formed to have a larger work function than the N-type semiconductor layer.

  The P-type semiconductor layer may be disposed in contact with the recombination prevention layer, and the Schottky junction layer may be formed to have a work function smaller than that of the P-type semiconductor layer. The PN semiconductor layer may be formed in a wafer form, and the wafer may be formed of silicon or GaAs. The PN semiconductor layer may be formed of an organic material.

  An antireflection film may be deposited on the Schottky bonding layer, and the antireflection film may be formed of SiOx or SiN. The antireflection film may be formed to have a thickness of 0.1 nm to 100 nm.

  The first electrode is disposed so that a light transmissive substrate is in contact therewith, and the PN semiconductor layer is disposed between a P-type semiconductor layer and an N-type semiconductor layer, and between the P-type semiconductor layer and the N-type semiconductor layer. It may be formed in the form of a thin film having an I (Intrinsic) type semiconductor layer.

  A solar cell according to another aspect of the present invention includes a PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer, a first electrode that is in ohmic contact with the first surface of the PN semiconductor layer, and the PN semiconductor layer. A Schottky junction layer that is Schottky-bonded to a second surface facing in the direction opposite to the first surface, and an ohmic junction that is ohmic-bonded to the second surface of the PN semiconductor layer and arranged in parallel with the Schottky junction layer Electrically connecting a metal layer, a first front electrode formed on the Schottky junction layer, a second front electrode formed on the ohmic metal layer, the second front electrode and the first electrode; First wiring to be connected, and second wiring to electrically connect the first front electrode and the first electrode.

  A solar cell according to another aspect of the present invention includes a PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer, a first ohmic metal layer in ohmic contact with the first surface of the PN semiconductor layer, and the PN A first Schottky junction layer that is Schottky-bonded to the first surface of the semiconductor layer; a second ohmic metal layer that is ohmic-bonded to a second surface facing away from the first surface of the PN semiconductor layer; and the PN semiconductor A second Schottky junction layer formed by Schottky junction with the second surface of the layer, a first front electrode formed on the first Schottky junction layer, and a second layer formed on the first ohmic metal layer. A first wiring electrically connecting the first front electrode and the second front electrode; a second wiring electrically connecting the first front electrode and the second ohmic metal layer; ,including.

  Here, the first Schottky junction layer is disposed at a position corresponding to the second ohmic metal layer in the vertical direction, and the first ohmic metal layer is positioned at a position corresponding to the second Schottky junction layer in the vertical direction. The second Schottky junction layer and the second ohmic metal layer may be disposed so as to contact each other.

  A solar cell according to another aspect of the present invention includes a PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer, a first ohmic metal layer in ohmic contact with the first surface of the PN semiconductor layer, and the PN A first Schottky junction layer that is Schottky bonded to the first surface of the semiconductor, a second ohmic metal layer that is ohmic-bonded to a second surface facing away from the first surface of the PN semiconductor layer, and the PN semiconductor layer A second Schottky junction layer formed by Schottky junction with the second surface, a first front electrode formed on the first Schottky junction layer, and a second front surface formed on the first ohmic metal layer. An electrode, a first wiring that electrically connects the first front electrode and the second Schottky junction layer, and a second wiring that electrically connects the second front electrode and the second ohmic metal layer And including.

  Here, the first Schottky junction layer is disposed at a position corresponding to the second ohmic metal layer in the vertical direction, and the first ohmic metal layer is positioned at a position corresponding to the second Schottky junction layer in the vertical direction. The second Schottky junction layer and the second ohmic metal layer may be spaced apart.

  A solar cell according to another aspect of the present invention includes a light-transmitting substrate, a P-type semiconductor layer, an N-type semiconductor layer, and the P-type semiconductor layer and the N-type semiconductor layer formed on the light-transmitting substrate. A PN semiconductor layer having an I (Intrinsic) type semiconductor layer disposed between the first PN semiconductor layer, a first Schottky junction layer bonded to the first surface of the PN semiconductor layer, and the first surface of the PN semiconductor layer And a second Schottky junction layer disposed between the light transmissive substrate and the PN semiconductor layer, and formed on the first Schottky junction layer. A first recombination preventing layer formed of an insulating material disposed between the first Schottky junction layer and the PN semiconductor layer, the second Schottky junction layer, and the PN Between the semiconductor layer and Comprising a second recombination preventing layer is formed of a material having an edge property, the.

  The first Schottky junction layer is formed of a material having a work function larger than that of the N-type semiconductor layer, and is in Schottky junction with the N-type semiconductor layer, and the second Schottky junction layer is more than the P-type semiconductor layer. Is formed of a material having a smaller work function and is Schottky-bonded to the P-type semiconductor layer, and the first Schottky junction layer is formed of a material having a work function smaller than that of the P-type semiconductor layer. A Schottky junction may be formed on the semiconductor layer, and the second Schottky junction layer may be formed of a material having a larger work function than the N-type semiconductor layer, and may be Schottky-bonded to the N-type semiconductor layer.

  The solar cell is disposed between the first Schottky junction layer and the PN semiconductor layer, and includes a first recombination prevention layer formed of an insulating material, the second Schottky junction layer, It may further include a second recombination preventing layer disposed between the PN semiconductor layer and formed of an insulating material.

  A method for manufacturing a solar cell according to an embodiment of the present invention includes a PN semiconductor layer preparation step of preparing a PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer, and insulation on the PN semiconductor layer. A recombination prevention layer forming step of forming a recombination prevention layer; a Schottky junction layer formation step of forming a metal layer bonded to the PN semiconductor layer; and a conductive front electrode on the Schottky junction layer Forming a front electrode.

  The PN semiconductor layer forming step may include a wafer doping step of doping the wafer to form an N-type semiconductor layer, and a first electrode forming step of forming a first electrode on the back surface of the PN semiconductor layer. The preparation step may further include a Fermi level adjustment step of increasing the Fermi level of the N-type semiconductor layer.

  Since the solar cell according to the present invention forms two solar cells in which a PN junction semiconductor layer and a Schottky junction layer are connected in series, photoelectric efficiency is improved because light is converted into electricity. Also, since two depletion regions are formed, the open circuit voltage (OCV) is improved.

  Furthermore, by forming Schottky junction layers on both sides of the PN junction semiconductor layer, there is an effect that three solar cells are connected in series. This not only facilitates the production of solar cells connected in series, but also improves the light efficiency and open circuit voltage of the solar cells.

It is sectional drawing which shows the solar cell which concerns on 1st Embodiment of this invention. It is a top view which shows the solar cell which concerns on 1st Embodiment of this invention. It is a flowchart for demonstrating the manufacturing method of the solar cell which concerns on 1st Embodiment of this invention. It is a schematic block diagram for demonstrating the working principle of the PN semiconductor layer of the solar cell which concerns on 1st Embodiment of this invention. It is a schematic block diagram for demonstrating the principle of operation of the Schottky junction layer and N type semiconductor layer of the solar cell which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on 3rd Embodiment of this invention. It is a top view which shows the solar cell which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on the modification of 5th Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on 6th Embodiment of this invention. It is sectional drawing which shows the solar cell which concerns on 7th Embodiment of this invention.

  In the present invention, “to up” means to be located above or below the target member, and does not necessarily mean to be located at the top with respect to the direction of gravity. In this description, “PN junction” means a structure in which a P-type semiconductor and an N-type semiconductor are joined, and a PIN junction in which an I-type semiconductor is interposed between the P-type semiconductor and the N-type semiconductor. It is defined as a PN junction in a broad sense including

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out. However, the present invention can be realized in various different forms, and is not limited to the embodiments described below. In the drawings, parts unnecessary for the description are omitted in order to clearly describe the present invention, and the same reference numerals are given to the same or similar components throughout the specification.

  FIG. 1 is a cross-sectional view showing a solar cell according to the first embodiment of the present invention. Referring to FIG. 1, the solar cell according to this embodiment includes a PN semiconductor layer 13, a first electrode 11 disposed so as to be in contact with the first surface of the PN semiconductor layer 13, and the PN semiconductor layer 13. A Schottky junction layer 15 disposed so as to be in contact with the second surface facing in the opposite direction to the first surface, and a recombination prevention layer 14 formed between the Schottky junction layer 15 and the PN semiconductor layer 13, The second electrode 12 is formed so as to be in contact with the Schottky junction layer 15.

  The PN semiconductor layer 13 is formed in a wafer form, and includes a P-type semiconductor layer 131 and an N-type semiconductor layer 132. The PN semiconductor layer 13 may be formed of crystalline silicon, and the PN semiconductor layer 13 may be obtained by doping an N-type material into crystalline silicon having P-type properties. The wafer may be formed of GaAs in addition to silicon.

  The present invention is not limited to this, and the PN semiconductor layer may be formed of an organic material. At this time, the PN semiconductor layer may be an N-type material (Electron donor) such as PPV, P3HT, or P3OT. P-type substances (Electron acceptors) such as C60, PCBCR, and PCBCa may be applied.

  On the back surface of the PN semiconductor layer 13, the first electrode 11 coupled by an ohmic junction is formed. The first electrode 11 may be formed entirely on the back surface of the PN semiconductor layer 13 and may be formed of a metal material such as aluminum.

  In the PN semiconductor layer 13, a P-type semiconductor layer 131 is disposed on the back side, and an N-type semiconductor layer 132 is disposed on the front side. On the other hand, a recombination prevention layer 14 is formed on the front surface of the PN semiconductor layer 13. The recombination prevention layer 14 may be formed of a material including an insulating oxide, SiOx, SiNx, or the like. The recombination prevention layer 14 is formed with a thickness of 0.1 nm to 10 nm, and improves voltage characteristics by preventing recombination of carriers generated by light. If the thickness of the recombination prevention layer 14 is formed to be smaller than 0.1 nm, a problem that excited electrons recombine with holes occurs, and the thickness of the recombination prevention layer 14 further exceeds 10 nm. If it is formed large, there arises a problem that the resistance increases excessively.

  In the present embodiment, an example in which the recombination preventing layer 14 is formed between the PN semiconductor layer 13 and the Schottky junction layer 15 for the purpose of improving the light efficiency is illustrated, but the present invention is limited to this. The Schottky junction layer 15 may be formed so as to be in direct contact with the PN semiconductor layer 13.

  On the recombination preventing layer 14, a Schottky junction layer 15 that is in Schottky junction with the PN semiconductor layer 13 is formed. The Schottky junction layer 15 is disposed so as to face the N-type semiconductor layer 132 and is made of a material having a work function larger than that of the N-type semiconductor layer 132. The material of the Schottky junction layer 15 is not limited to a specific metal, and various types of metals may be applied as long as they have a work function larger than that of the N-type semiconductor layer 132. Further, the Schottky bonding layer 15 may be formed of a material containing metal, ITO, ATO, IZO, AZO, or the like. If ITO, ATO, IZO, AZO or the like is mixed in the Schottky junction layer 15, the light transmittance of the Schottky junction layer 15 is improved without lowering the electrical conductivity.

  The thickness of the Schottky junction layer 15 may be 1 nm to 20 nm. If the thickness of the Schottky junction layer 15 is smaller than 1 nm, a problem that a depletion layer is not properly formed may occur. If the thickness of the Schottky junction layer 15 is further larger than 20 nm, There arises a problem that the transmission efficiency is remarkably lowered. An antireflection film 16 is formed on the Schottky bonding layer 15, and the antireflection film 16 is disposed between the Schottky bonding layer 15 and the second electrode 12. The antireflection film 16 may be formed of SiOx or SiN, and may be formed with a thickness of 0.1 nm to 100 nm.

  The recombination preventing layer 14 and the Schottky junction layer 15 are formed with a sufficiently small thickness so as to have light transmittance. The larger the light transmittance between the recombination preventing layer 14 and the Schottky bonding layer 15 is, the more advantageous, but it is formed so that at least 50% or more of light can be transmitted.

  As shown in FIGS. 1 and 2, the second electrode 12 is formed on the Schottky junction layer 15, and the second electrode 12 is formed in a band shape that is long in one direction. The second electrode is formed of a metal having excellent electrical conductivity such as silver (Ag) or platinum (Pt). The second electrode 12 may be disposed on a surface facing the opposite direction to the first electrode 11, and the first electrode 11 may be defined as a back electrode and the second electrode 12 may be defined as a front electrode.

  A plurality of the second electrodes 12 are spaced apart, and a bus bar 17 that electrically connects the second electrodes 12 is formed on each second electrode 12. The second electrode 12 and the bus bar 17 may be formed of Cu, Ag, or the like having low resistance and excellent electrical conductivity.

  The manufacturing method of the solar cell according to the first embodiment will be described with reference to FIG. The solar cell 101 manufacturing method according to the present embodiment includes a PN semiconductor layer 13 preparation step (S101), a recombination prevention layer 14 formation step (S102), a Schottky junction layer 15 formation step (S103), and a second step. Forming an electrode 12 (S104).

  The PN semiconductor layer 13 preparation step (S101) includes a wafer doping step of doping the wafer to form the N-type semiconductor layer 132 on the P-type semiconductor layer 131, and a first electrode for forming the first electrode 11 on the back surface of the wafer. 11 forming step.

  The wafer may be formed of crystalline silicon commonly used for solar cells, and since the method for manufacturing the wafer is widely known, a detailed description thereof will be omitted.

  The wafer doping step may be formed by doping a Group 5 material such as phosphorus (P) or asenide (As). In the first electrode 11 formation step, the first electrode 11 is formed on the back surface of the wafer by a method such as vapor deposition or coating of a metal such as aluminum.

The preparation step (S101) of the PN semiconductor layer 13 may further include a Fermi level adjustment step of increasing the Fermi level of the N-type semiconductor layer 132. In the Fermi level adjusting step, after the N-type semiconductor layer 132 is formed, the Fermi level of the N-type semiconductor layer 132 may be increased using a gas such as ammonia (NH ₃ ) or oxygen. Fermi level adjustment methods include a method of reacting and heat-treating with functional molecules such as potassium (K) and bromine (Br), a method of using a connecting chain with a polymer (PEI) material, and aluminum. A method of doping a metal or the like may be applied.

  On the other hand, in the recombination prevention layer 14 formation step (S102), a substance such as Oxide, SiOx, SiNx is formed on the N-type semiconductor layer 132 by a method such as vapor deposition. In the Schottky bonding layer 15 formation step (S103), the Schottky bonding layer 15 is formed on the recombination prevention layer 14 by a method such as vapor deposition, sputtering, or coating. The Schottky bonding layer 15 may be formed of a material containing metal, ITO, ATO, IZO, AZO, or the like.

  In the second electrode 12 formation step (S104), the second electrode 12 is formed on the Schottky junction layer 15 by a method such as vapor deposition or coating. The second electrode may be formed of a metal having excellent electrical conductivity such as silver (Ag) or platinum (Pt).

  The operation of the solar cell 101 according to the first embodiment will be described with reference to FIGS. 4a and 4b. When light is incident, electrons are excited by light in the first depletion region (A1) where the P-type semiconductor layer 131 and the N-type semiconductor layer 132 are in contact, and the excited electrons move to the N-type semiconductor layer 132 to cause a voltage difference. Occurs. In addition, a second depletion region (A2) is formed at a portion where the N-type semiconductor layer 132 and the Schottky junction layer 15 are in contact with each other. When light is incident, free electrons are generated in the second depletion region (A2). Causes a voltage difference. If electrons are accumulated in the N-type semiconductor layer 132, the electrons move over the barrier to the Schottky junction layer 15 due to the tunnel effect, and are extracted to the outside.

  According to the present embodiment, the PN semiconductor layer 13 becomes one solar cell, and the N-type semiconductor layer 132 and the Schottky junction layer 15 become another solar cell, so that the two solar cells are connected in series. Has the same effect as the one. Further, by forming the Schottky junction layer 15 on a conventional solar cell in the form of a wafer, it is possible to easily form a multiple solar cell, so that the manufacturing is easy and the cost can be reduced. it can. Since the solar cell of this description can obtain the solar cell connected in series by forming one Schottky junction layer 15, rather than forming a plurality of PIN semiconductor layers like a thin film solar cell, It is much more advantageous in production.

  FIG. 5 is a cross-sectional view showing a solar cell according to the second embodiment of the present invention. Referring to FIG. 5, the solar cell 102 according to this embodiment includes a PN semiconductor layer 23, a first electrode 21 disposed so as to be in contact with one surface of the PN semiconductor layer 23, and the PN semiconductor layer 23. A Schottky junction layer 25 disposed so as to face the other surface facing in the opposite direction to the one surface, a recombination prevention layer 24 formed between the Schottky junction layer 25 and the PN semiconductor layer 23, and a Schottky junction. A second electrode 22 formed so as to be in contact with the layer 25.

  The solar cell 102 according to the present embodiment has the same structure as that of the solar cell according to the first embodiment except for the structure of the PN semiconductor layer 23 and the Schottky junction layer 25, and therefore, redundant description of the same structure is omitted. To do.

  The PN semiconductor layer 23 is formed of a semiconductor wafer and includes an N-type semiconductor layer 231 and a P-type semiconductor layer 232. The PN semiconductor layer 23 may be formed of crystalline silicon, and the PN semiconductor layer 23 may be obtained by doping a crystalline silicon having N-type properties with a P-type material.

  The Schottky junction layer 25 is in Schottky junction with the P-type semiconductor layer 232, and the Schottky junction layer 25 is formed of a material having a work function smaller than that of the P-type semiconductor layer 232. Thereby, a depletion region is also formed in a region where Schottky junction layer 25 and P-type semiconductor layer 232 are in contact with each other.

  Thus, according to this embodiment, a solar cell having a structure in which a PN junction solar cell and a Schottky junction solar cell are connected in series can be obtained.

  FIG. 6 is a cross-sectional view showing a solar cell according to the third embodiment of the present invention. FIG. 7 is a plan view showing a solar cell according to the third embodiment of the present invention.

  Referring to FIGS. 6 and 7, the solar cell 103 according to this embodiment includes a PN semiconductor layer 33, a first electrode 31 disposed so as to be in contact with one surface of the PN semiconductor layer 33, and a PN semiconductor layer 33. A recombination prevention layer 34 disposed so as to be in contact with the other surface facing in the opposite direction to the one surface, a Schottky junction layer 35 formed on the recombination prevention layer 34, and an ohmic metal layer 36.

  The PN semiconductor layer 33 includes a P-type semiconductor layer 331 and an N-type semiconductor layer 332 formed on the P-type semiconductor layer 331, and has the same structure as the PN semiconductor layer according to the first embodiment. The recombination preventing layer 34 is formed of a material such as Oxide, SiOx, SiNx.

  A Schottky junction layer 35 and an ohmic metal layer 36 are spaced apart from each other on the recombination prevention layer 34, and the Schottky junction layer 35 is formed of a material having a work function larger than that of the N-type semiconductor layer 332. A Schottky junction is made to layer 332. The ohmic metal layer 36 is formed of a material having a work function smaller than that of the N-type semiconductor layer 332 and is in ohmic contact with the N-type semiconductor layer 332. The Schottky junction layer 35 and the ohmic metal layer 36 are arranged side by side on the same plane.

  A first front electrode 321 is disposed on the Schottky junction layer 35, and a second front electrode 322 is disposed on the ohmic metal layer 36. The Schottky junction layer 35, the ohmic metal layer 36, the first front electrode 321, the second front electrode 322, and the recombination prevention layer 34 have sufficiently small thicknesses so that light enters the PN semiconductor layer 33.

  On the other hand, the first electrode 31 may be formed so as to be in contact with the P-type semiconductor layer 331, and the first electrode 31 may be formed of a metal such as aluminum.

  According to the present embodiment, when light is incident, electrons are generated in the depletion region where the P-type semiconductor layer 331 and the N-type semiconductor layer 332 are in contact with each other, and the depletion where the N-type semiconductor layer 332 and the Schottky junction layer 35 are in contact with each other. Electrons are generated in the region.

  Electrons formed between the Schottky junction layer 35 and the N-type semiconductor layer 332 move to the first electrode 31 through the P-type semiconductor layer 331 or to the second front electrode 322. On the other hand, electrons formed between the P-type semiconductor layer 331 and the N-type semiconductor layer 332 move to the first electrode 31.

  According to this embodiment, in the flow of electrons moving from the first front electrode 321 to the first electrode 31, the Schottky junction layer 35 and the N-type semiconductor layer 332 become the first unit cell, and the P-type semiconductor layer 331 The N-type semiconductor layer 332 becomes the second unit battery. In addition, in the flow of electrons moving from the first front electrode 321 to the second front electrode 322, the Schottky junction layer 35 and the N-type semiconductor layer 332 become the third unit cell. Thus, according to this embodiment, three solar cells are formed.

  If the second front electrode 322 and the first electrode 31 are electrically connected through the first wiring 371, and the first front electrode 321 and the first electrode 31 are connected to the storage battery 373 through the second wiring 372, the first unit is obtained. The battery and the second unit battery are connected in series, and the third unit battery is connected to them in parallel.

  FIG. 8 is a cross-sectional view showing a solar cell according to the fourth embodiment of the present invention. Referring to FIG. 8, the solar cell 104 according to this embodiment includes a PN semiconductor layer 43, a first electrode 48 disposed so as to be in contact with one surface of the PN semiconductor layer 43, and the PN semiconductor layer 43. A Schottky junction layer 46 disposed so as to face the other surface facing the opposite direction, a recombination preventing layer 45 formed between the Schottky junction layer 46 and the PN semiconductor layer 43, and a Schottky junction layer. And a second electrode 47 formed so as to be in contact with 46.

  The solar cell 104 according to this embodiment is formed as a thin-film solar cell formed on the light transmissive substrate 41. The light transmissive substrate 41 may be formed of a glass or polymer substrate. An antireflection film on which nano-sized fine protrusions are formed may adhere to the light-transmitting substrate 41. The antireflection film may be formed of SiOx or SiN, and may be formed with a thickness of 0.1 nm to 100 nm.

  The light transmissive substrate 41 is disposed in contact with the first electrode 48, and the first electrode 48 is formed on the light transmissive substrate 41. The first electrode 48 is formed of a transparent material such as ITO, IZO, or FTO. On the other hand, the PN semiconductor layer 43 is formed in a thin film form, and an I (intrinsic) type semiconductor layer 433 formed between the P type semiconductor layer 431 and the N type semiconductor layer 432 and between the P type semiconductor layer 431 and the N type semiconductor layer 432. including. Since the PIN junction structure of such a thin film solar cell is widely known, detailed description thereof is omitted. Here, the I (intrinsic) type semiconductor layer 433 is formed of an intrinsic semiconductor material.

  Such a PN semiconductor layer may be formed of a material containing InP, InGaP, CdSe, CdS, ZnSe, ZnS, ZnTe, or the like.

  On such a PN semiconductor layer 43, a recombination preventing layer 45, a Schottky junction layer 46, and a second electrode 47 are sequentially laminated. Since the recombination prevention layer 45, the Schottky junction layer 46, and the second electrode 47 have the same structure as that of the solar cell according to the first embodiment, overlapping description is omitted.

  Thus, according to this embodiment, a multiple solar cell can be easily manufactured by forming the Schottky junction layer 46 on a thin film solar cell.

  FIG. 9 is a sectional view showing a solar cell according to the fifth embodiment of the present invention. The solar cell 105 according to the present embodiment includes a PN semiconductor layer 53, a first Schottky junction layer 551 arranged to face one surface of the PN semiconductor layer 53, a first ohmic metal layer 552, and a PN semiconductor layer. 53, a second Schottky junction layer 541 arranged to face the other surface facing the opposite direction to one surface, and a second ohmic metal layer 542.

  The first Schottky junction layer 551 is Schottky bonded to the first surface of the PN semiconductor layer 53, and the first ohmic metal layer 552 is ohmic bonded to the first surface of the PN semiconductor layer 53. The second Schottky junction layer 541 has a Schottky junction with a second surface facing away from the first surface of the PN semiconductor layer 53, and the second ohmic metal layer 542 has an ohmic junction with the second surface of the PN semiconductor layer 53.

  A first recombination prevention layer 57 is formed between the PN semiconductor layer 53 and the first Schottky junction layer 551 and the first ohmic metal layer 552, and the PN semiconductor layer 53 and the second Schottky junction layer 541 A second recombination prevention layer 56 is formed between the second ohmic metal layer 542 and the second ohmic metal layer 542. A first front electrode 521 is formed on the first Schottky junction layer 551, and a second front electrode 522 is formed on the first ohmic metal layer 552.

  The solar cell 105 according to the present embodiment is formed as a thin-film solar cell formed on the light transmissive substrate 51. The light transmissive substrate 51 may be formed of a glass or polymer substrate.

  A second Schottky junction layer 541 and a second ohmic metal layer 542 are formed on the light transmissive substrate 51. The second Schottky junction layer 541 and the second ohmic metal layer 542 are arranged side by side on the light transmissive substrate 51.

  On the other hand, the PN semiconductor layer 53 is formed in a thin film form, and an I (intrinsic) type semiconductor layer 533 formed between the P type semiconductor layer 531 and the N type semiconductor layer 532 and between the P type semiconductor layer 531 and the N type semiconductor layer 532. including.

  A recombination prevention layer 57 is formed on such a PN semiconductor layer, and a first Schottky junction layer 551 and a first ohmic metal layer 552 are formed side by side on the recombination prevention layer 57.

  A second ohmic metal layer 542 is formed at a lower position corresponding to the first Schottky junction layer 551, and a second Schottky junction layer 541 is formed at a lower position corresponding to the first ohmic metal layer 552.

  The first Schottky junction layer 551 is formed of a material having a work function larger than that of the N-type semiconductor layer 532, and the second Schottky junction layer 541 is formed of a material having a work function smaller than that of the P-type semiconductor layer 531. . The first ohmic metal layer 552 is formed of a material having a work function smaller than that of the N-type semiconductor layer 532, and the second ohmic metal layer 542 is formed of a material having a work function higher than that of the P-type semiconductor layer 531. .

  According to the present embodiment, electrons are generated between the first Schottky junction layer 551 and the N-type semiconductor layer 532, and between the PN semiconductor layer 53, the second Schottky junction layer 541 and the P-type semiconductor layer 531. The

  In detail, the electrons generated in the PN semiconductor layer 53 located between the first Schottky junction layer 551 and the N-type semiconductor layer 532 and below the first Schottky junction layer 551 are second electrons. The electrons moved to the ohmic metal layer 542 and electrons generated in the PN semiconductor layer 53 located between the second Schottky junction layer 541 and the P-type semiconductor layer 531 and on the second Schottky junction layer 541 are generated in the second shot. It moves to the key bonding layer 541.

  Thus, according to the present embodiment, the first Schottky junction layer 551 and the N-type semiconductor layer 532 serve as the first unit cell, and the PN semiconductor layer 53 located under the first Schottky junction layer 551 is the second unit cell. The second Schottky junction layer 541 and the P-type semiconductor layer 531 become the third unit cell, and the PN semiconductor layer 53 located on the second Schottky junction layer 541 becomes the fourth unit cell.

  The first front electrode 521 and the second front electrode 522 are electrically connected by the first wiring 581, the second Schottky junction layer 541 and the second ohmic metal layer 542 are in contact with each other and electrically connected, If the front electrode 521 and the second ohmic metal layer 542 are electrically connected to the storage battery 583 through the second wiring 582, the first unit battery and the second unit battery are connected in series to connect the third unit battery and the second unit battery. Four unit batteries are connected in series, and battery sets connected in series are connected in parallel.

  FIG. 10 is a cross-sectional view showing a solar cell according to a modification of the fifth embodiment of the present invention. Referring to FIG. 10, the second Schottky junction layer 541 and the second ohmic metal layer 542 according to the present embodiment are spaced apart from each other. Except for the configuration and wiring, the structure is the same as that of the solar cell according to the fifth embodiment.

  The first front electrode 521 is electrically connected through the second Schottky junction layer 541 and the first wiring 591, and the storage battery 593 is electrically connected to the second front electrode 522 and the second ohmic metal layer 542 through the second wiring 592. Are connected.

  Thereby, according to this embodiment, the 1st unit cell, the 2nd unit cell, the 3rd unit cell, and the 4th unit cell connect in series.

  FIG. 11 is a cross-sectional view showing a solar cell according to the sixth embodiment of the present invention. Referring to FIG. 11, the solar cell 106 according to the present embodiment includes a light transmissive substrate 61, a PN semiconductor layer 63 formed on the light transmissive substrate 61, and a first PN semiconductor layer 63. A first Schottky junction layer 66 having a Schottky junction with the surface, a second Schottky junction layer 68 having a Schottky junction with the second surface of the PN semiconductor layer 63, and an electrode formed on the first Schottky junction layer 66 67. Here, the second surface of the PN semiconductor layer 63 is a surface facing in the opposite direction to the first surface.

  The solar cell 106 according to the present embodiment is formed as a thin-film solar cell formed on the light transmissive substrate 61. The light transmissive substrate 61 may be formed of a glass or polymer substrate.

  The PN semiconductor layer 63 is formed in a thin film form, and includes a P-type semiconductor layer 631 and an N-type semiconductor layer 632, and an I-type semiconductor layer 633 formed between the P-type semiconductor layer 631 and the N-type semiconductor layer 632. Since the PIN junction structure of such a thin film solar cell is widely known, detailed description thereof is omitted.

  The first Schottky junction layer 66 is disposed on the PN semiconductor layer 63 and forms a Schottky junction with the N-type semiconductor layer 632. The first Schottky junction layer 66 is formed of a material having a work function larger than that of the N-type semiconductor layer 632. A first recombination prevention layer 65 made of an insulating material is formed between the first Schottky junction layer 66 and the N-type semiconductor layer.

  The second Schottky junction layer 68 is disposed between the light transmissive substrate 61 and the PN semiconductor layer 63 and is Schottky joined to the P-type semiconductor layer 631. The second Schottky junction layer 68 is formed of a material having a work function smaller than that of the P-type semiconductor layer 631.

  At this time, the second Schottky junction layer 68 is disposed in contact with the light-transmitting substrate, and a second recombination prevention layer made of an insulating material is provided between the second Schottky junction layer 68 and the P-type semiconductor layer 631. Layer 64 is formed.

  The first Schottky junction layer 66 and the second Schottky junction layer 68 are formed with a thickness of 1 nm to 20 nm so as to have optical transparency. According to this, electric power can be produced by light incident on both sides.

  If a storage battery is connected to the electrode 67 and the second Schottky junction layer 68, the first Schottky junction layer 66 and the N-type semiconductor layer 632 constitute one solar cell, and the PN semiconductor layer 63 constitutes one solar cell. None, when the P-type semiconductor layer 631 and the second Schottky junction layer 68 form one solar cell, a structure in which three solar cells are connected in series is obtained.

  According to this embodiment, by forming the Schottky junction layers 66 and 68 on both surfaces of the PN semiconductor layer 63, a structure in which three solar cells are connected in series can be easily manufactured.

  FIG. 12 is a cross-sectional view showing a solar cell according to the seventh embodiment of the present invention. Referring to FIG. 12, the solar cell 107 according to this embodiment includes a light transmissive substrate 71, a PN semiconductor layer 73 formed on the light transmissive substrate 71, and a first PN semiconductor layer 73. A first Schottky junction layer 76 having a Schottky junction with the surface, a second Schottky junction layer 78 having a Schottky junction with the second surface of the PN semiconductor layer 73, and an electrode formed on the first Schottky junction layer 76 77. Here, the second surface of the PN semiconductor layer 73 is a surface facing in the opposite direction to the first surface.

  The solar cell 107 according to this embodiment is formed as a thin-film solar cell formed on the light transmissive substrate 71. The light transmissive substrate 71 may be formed of a glass or polymer substrate.

  The PN semiconductor layer 73 is formed in a thin film form, and includes an N-type semiconductor layer 731 and a P-type semiconductor layer 732, and an I-type semiconductor layer 733 formed between the N-type semiconductor layer 731 and the P-type semiconductor layer 732. Since the PIN junction structure of such a thin film solar cell is widely known, detailed description thereof is omitted.

  The first Schottky junction layer 76 is disposed on the PN semiconductor layer 73 and forms a Schottky junction with the P-type semiconductor layer 732. The first Schottky junction layer 76 is formed of a material having a work function smaller than that of the P-type semiconductor layer 732. A first recombination prevention layer 75 made of an insulating material is formed between the first Schottky junction layer 76 and the P-type semiconductor layer.

  The second Schottky junction layer 78 is disposed between the light transmissive substrate 71 and the PN semiconductor layer 73, and is in Schottky junction with the N-type semiconductor layer 731. The second Schottky junction layer 78 is formed of a material having a work function larger than that of the N-type semiconductor layer 731.

  At this time, the second Schottky junction layer 78 is disposed so as to be in contact with the light transmissive substrate 71, and a second recombination made of an insulating material is provided between the second Schottky junction layer 78 and the N-type semiconductor layer 731. A prevention layer 74 is formed.

  The first Schottky junction layer 76 and the second Schottky junction layer 78 are formed with a thickness of 1 nm to 20 nm so as to have optical transparency. According to this, electric power can be produced by light incident on both sides.

  If a storage battery is connected to the electrode 77 and the second Schottky junction layer 78, the first Schottky junction layer 76 and the N-type semiconductor layer 731 constitute one solar cell, and the PN semiconductor layer 73 constitutes one solar cell. Since the P-type semiconductor layer 732 and the second Schottky junction layer 78 form one solar cell, a structure in which three solar cells are connected in series is obtained.

  According to this embodiment, by forming the Schottky junction layers 76 and 78 on both surfaces of the PN semiconductor layer 73, a structure in which three solar cells are connected in series can be easily manufactured.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications are made within the scope of the claims, the detailed description of the invention and the attached drawings. Of course, this is also within the scope of the present invention.

Claims (25)

A PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer;
A first electrode in ohmic contact with the first surface of the PN semiconductor layer;
A Schottky junction layer that is Schottky bonded to a second surface of the PN semiconductor layer facing away from the first surface;
A second electrode formed in contact with the Schottky junction layer;
A solar cell including a recombination prevention layer disposed between the Schottky junction layer and the PN semiconductor layer and formed of an insulating material.   The solar cell according to claim 1, wherein the recombination preventing layer has a thickness of 0.1 nm to 10 nm.   The solar cell according to claim 1, wherein the N-type semiconductor layer is disposed in contact with the recombination prevention layer.   The solar cell according to claim 3, wherein the Schottky junction layer has a larger work function than the N-type semiconductor layer.   The solar cell according to claim 1, wherein the P-type semiconductor layer is disposed in contact with the recombination prevention layer.   The solar cell according to claim 5, wherein the Schottky junction layer has a smaller work function than the P-type semiconductor layer.   The solar cell according to claim 1, wherein the Schottky junction layer is formed of a metal.   2. The solar cell according to claim 1, wherein the Schottky junction layer is formed of any one or more materials selected from the group consisting of metal, ITO, ATO, IZO, and AZO.   The solar cell according to claim 1, wherein the PN semiconductor layer is formed of a wafer.   The solar cell according to claim 1, wherein the PN semiconductor layer is formed of an organic material.   The solar cell according to claim 1, wherein an antireflection film is attached on the Schottky junction layer.   The solar cell according to claim 11, wherein the antireflection film is formed of SiOx or SiN.   The solar cell according to claim 11, wherein the antireflection film has a thickness of 0.1 nm to 100 nm. The first electrode is disposed so that a light-transmitting substrate is in contact therewith,
The PN semiconductor layer is formed in a thin film form having a P-type semiconductor layer, an N-type semiconductor layer, and an I (Intrinsic) -type semiconductor layer disposed between the P-type semiconductor layer and the N-type semiconductor layer. 1. The solar cell according to 1. A PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer;
A first electrode in ohmic contact with the first surface of the PN semiconductor layer;
A Schottky junction layer that is Schottky bonded to a second surface of the PN semiconductor layer facing away from the first surface;
An ohmic metal layer that is in ohmic contact with the second surface of the PN semiconductor layer and is arranged alongside the Schottky junction layer;
A first front electrode formed on the Schottky junction layer;
A second front electrode formed on the ohmic metal layer;
A first wiring electrically connecting the second front electrode and the first electrode;
A solar cell comprising: a first wiring that electrically connects the first front electrode and the first electrode. A PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer;
A first ohmic metal layer in ohmic contact with the first surface of the PN semiconductor layer;
A first Schottky junction layer that is Schottky joined to the first surface of the PN semiconductor;
A second ohmic metal layer in ohmic contact with a second surface facing away from the first surface of the PN semiconductor layer;
A second Schottky junction layer that is Schottky joined to the second surface of the PN semiconductor layer;
A first front electrode formed on the first Schottky junction layer;
A second front electrode formed on the first ohmic metal layer;
A first wiring that electrically connects the first front electrode and the second front electrode;
A solar cell comprising: a second wiring that electrically connects the first front electrode and the second ohmic metal layer. The first Schottky junction layer is disposed at a position corresponding to the second ohmic metal layer in the vertical direction,
The first ohmic metal layer is disposed at a position corresponding to the second Schottky junction layer in a vertical direction;
The solar cell of Claim 16 arrange | positioned so that a 2nd Schottky junction layer and a 2nd ohmic metal layer may contact | abut. A PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer;
A first ohmic metal layer in ohmic contact with the first surface of the PN semiconductor layer;
A first Schottky junction layer that is Schottky joined to the first surface of the PN semiconductor;
A second ohmic metal layer in ohmic contact with a second surface facing away from the first surface of the PN semiconductor layer;
A second Schottky junction layer that is Schottky joined to the second surface of the PN semiconductor layer;
A first front electrode formed on the first Schottky junction layer;
A second front electrode formed on the first ohmic metal layer;
A first wiring that electrically connects the first front electrode and the second Schottky junction layer;
A solar cell comprising: a second wiring that electrically connects the second front electrode and the second ohmic metal layer. The first Schottky junction layer is disposed at a position corresponding to the second ohmic metal layer in the vertical direction,
The first ohmic metal layer is disposed at a position corresponding to the second Schottky junction layer in a vertical direction;
The solar cell of claim 18, wherein the second Schottky junction layer and the second ohmic metal layer are spaced apart. A light transmissive substrate;
A PN semiconductor layer formed on the light transmissive substrate and including a P-type semiconductor layer and an N-type semiconductor layer;
A first Schottky junction layer bonded to the first surface of the PN semiconductor layer;
A Schottky junction to a second surface of the PN semiconductor layer facing away from the first surface, and a second Schottky junction layer disposed between the light transmissive substrate and the PN semiconductor layer;
An electrode formed on the first Schottky junction layer;
A first recombination prevention layer disposed between the first Schottky junction layer and the PN semiconductor layer and formed of an insulating material;
A solar cell including a second recombination prevention layer disposed between the second Schottky junction layer and the PN semiconductor layer and formed of an insulating material. The first Schottky junction layer is formed of a material having a larger work function than that of the N-type semiconductor layer, and forms a Schottky junction with the N-type semiconductor layer.
The solar cell according to claim 20, wherein the second Schottky junction layer is formed of a material having a work function smaller than that of the P-type semiconductor layer, and forms a Schottky junction with the P-type semiconductor layer. The first Schottky junction layer is formed of a material having a work function smaller than that of the P-type semiconductor layer, and forms a Schottky junction with the P-type semiconductor layer.
21. The solar cell according to claim 20, wherein the second Schottky junction layer is formed of a material having a work function larger than that of the N-type semiconductor layer, and forms a Schottky junction with the N-type semiconductor layer. A PN semiconductor layer preparation step of preparing a PN semiconductor layer having a P-type semiconductor layer and an N-type semiconductor layer;
A recombination prevention layer forming step of forming an insulating recombination prevention layer on the PN semiconductor layer;
A Schottky junction layer forming step of forming a Schottky junction metal layer to the PN semiconductor layer;
A front electrode forming step of forming a conductive front electrode on the Schottky junction layer.   The PN semiconductor layer forming step includes a wafer doping step of doping the wafer to form an N-type semiconductor layer, and a first electrode forming step of forming a first electrode on the back surface of the PN semiconductor layer. The manufacturing method of the solar cell of description.   24. The method of manufacturing a solar cell according to claim 23, wherein the PN semiconductor layer preparation step further includes a Fermi level adjustment step of increasing the Fermi level of the N-type semiconductor layer.

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