Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/81—Bodies
  • H10H20/822—Materials of the light-emitting regions
  • H10H20/823—Materials of the light-emitting regions comprising only Group II-VI materials, e.g. ZnO

Definitions

• the present invention relates to a photoelectric conversion functional element (semiconductor optical device) using an I-I V group compound semiconductor crystal as a substrate, and in particular, to the composition of each layer in a photoelectric conversion functional device using a ZnTe single crystal as a substrate.
• an I-I V I compound semiconductor is a semiconductor having a wide gap, and therefore yellow light emission, green light emission, blue light emission and the like are possible. Therefore, in recent years, development of a highly efficient and long-lived photoelectric conversion functional device has been attempted using an I-I V I-group compound semiconductor crystal as a substrate.
• Japanese Unexamined 04 1 334 78 discloses, regarding the M g Z n x T e light emitting device having a cladding layer and the active layer composed of (0 ⁇ x ⁇ 1) on the p-type Z n T e substrate Technology is disclosed.
• p- Z nT e p one Mg 0 on the substrate.
• a semiconductor light emitting device is realized.
• the crystal quality becomes inferior because the lattice matching condition between the substrate and each layer formed on the substrate can not be satisfied, and it is therefore difficult to fabricate a light emitting device that can withstand practical use. there were.
• a Z nMg S e T e cladding layer substantially lattice-matched with the substrate and A technique has been proposed in which a Z nC d S e T e active layer is formed to form a II-VI compound semiconductor laser (Japanese Patent Laid-Open No. 10-27946).
• the structure is substantially lattice matched from the p-type Z n T e substrate to the n-side cladding layer above the active layer, Generation of stress due to strain caused by lattice mismatch in the vicinity of the active layer can be completely suppressed.
• the band gap energy E g can be obtained by changing the composition. Since it can be changed continuously, there is an advantage that it is easy to design an active layer having an emission wavelength that matches the purpose.
• quaternary systems have the advantage of being able to optimize another degree of freedom, such as the lattice constant and the refractive index of light.
• the present invention relates to a photoelectric conversion function element having an active layer, a clad layer, and a p-type Z n T e single crystal substrate, and a clad layer which substantially satisfies the condition capable of lattice matching with the substrate.
• a photoelectric conversion functional device having a cladding layer it is an object of the present invention to provide a photoelectric conversion functional device having excellent device characteristics by adjusting a band gap between layers. Disclosure of the invention
• the present invention is a photoelectric conversion functional device having an active layer and a clad layer satisfying a condition that allows substantially lattice matching with a P-type Z n T e single crystal substrate,
• the band gap of the cladding layer may be 0.30 e V or more larger than the band gap of the active layer.
• the conversion functional element wherein the band gap of the light guide layer is larger than the band gap of the active layer by at least 0.1 e V, and the pand gap of the cladding layer is larger than that of the active layer of 0.30 e V. large and a photoelectric conversion function element as the light guide layer is larger 0. 2 e V or more than the bandgap of 0
• the confinement efficiency of the carrier can be increased, and a photoelectric conversion functional device having excellent device characteristics can be manufactured.
• the band gap of the cladding layer be larger than the band gap of the active layer by 50 eV or more.
• the p-side optical guiding layer provided p side of the active layer, Z n x (Mg y B ei. Y) 1-X T e or ⁇ n x (Mg y B e ) X,. X T e / Z ⁇ e Superlattices were constructed.
• the composition x, y is a value satisfying 0, 1, 2, 0 ⁇ y ⁇ 1. This allows the p-side light guide layer to be lattice matched to the ZnTe substrate.
• the ⁇ -side optical guiding layer provided n side of said active layer, and to constitute with Mg S e x T ei _ x ZZ nT e superlattice.
• composition X be a value that satisfies 0 ⁇ ⁇ 1.
• the band gap can be adjusted not only by the composition x but also by the layer thickness ratio of the superlattice, so the band gap can be relatively easily obtained with desired emission characteristics. Can be realized.
• the P-side cladding layer provided on the p-side of the active layer may be represented by Z n x (M gy B e 1-y ) 1 -x T e or Z n x (M y B e) 1 - ⁇ It was made to consist of e / Z n Te superlattices.
• the composition x, y is set to a value satisfying 0, 1, 2, 0 ⁇ y.
• the P-side cladding layer can be lattice-matched to the ZnTe substrate, and a high p-type carrier concentration can be obtained as in the case of ZnTe and BeTe.
• the P-side cladding layer is composed of Z n x (M y B e x . Y ) e and Z n T e If the superlattice is used, there is an advantage that the pand gap of the p-side cladding layer can be adjusted by both the composition of Z n Mg B e T e and the layer thickness ratio of the super lattice. In addition, stable growth is possible by making the P-side cladding layer and the p-side light guide layer the same configuration.
• the lattice constant of Z nTe is 6.1 A
• the lattice constant of M g T e When the lattice constant of 6.35 A and B.sub.eTe is 6.56 2 A, the composition of the above Z n x (M g y B ee is Z n x (Mg 0. 658 B e 0. 342) . It is e (0 ⁇ x ⁇ 1).
• the composition of Z nMg B e T e constituting the p-side cladding layer is Z n x (M g 0.658 B e o. 342 ) e and lattice matching is made with Z n T e, p
• the side cladding layer can be stably grown.
• the n-side cladding layer provided on the n-side of the active layer is configured by a M g S e x T e x .
• X Z n T e superlattice is configured by a M g S e x T e x .
• X Z n T e superlattice is configured by a M g S e x T e x .
• X Z n T e superlattice the composition X has a value satisfying 0 ⁇ X ⁇ 1.
• the n-side cladding layer can be easily deposited on the n-side light guide layer substantially lattice-matched with Z nTe by forming the n-side cladding layer with the M g S e X T e Z n T e superlattice.
• the crystal structure of Z nT e is of zinc blende type
• the crystal structure of M g S e T e is of wurtzite type, so it is substantially lattice-matched with Z n T e.
• the band gap can be relatively easily adjusted by the layer thickness ratio of the Mg S e x T ei .
• X ZZ n T e superlattice since the refractive index of Mg S e T e is lower than that of Z n T e, there is an advantage that the light confinement effect is large.
• X T e is considering to be equivalent to (Z nT e) x [( Mg T e) y (B e T e) x. Y],
• the condition for lattice matching of Z n x (M y B ee and Z n T e is independent of the composition X,
• the band gap of Z n x (Mg 0. 658 B e 0. 342 ) 1-X T e constituting the p-side cladding layer and the p-side optical guide layer satisfies the equation (2) ′ (3) .
• the band gap E b in the case where the side optical guide layer is formed of Z n Mg B e T e / Z n T e superlattice is (2) do it,
• Mg S e X T e x . X (0 ⁇ x ⁇ 1) constituting the n-side cladding layer and the n-side optical guide layer first described method for calculating the composition for Z nT e lattice-matched If Mg S e x T is considered to be equivalent to (M g S e) x (M g T e), the condition for lattice matching between Mg S e x T ei _ x and Z nT e is
• B e Z n C d T e Z n Mg S e T e, Mg S e T e / Z n T e superlattice, B e Mg Z n T e , Z n C d S e T e ', etc. can be considered.
• the active layer is composed of B e x Z n y C e (0 ⁇ 1, 0 ⁇ 1, 1, 0 ⁇ x + y ⁇ 1)
• a method of determining the composition of the active layer Explain Ru.
• Y T e is (B e T e) x ( Z nT e) y (C d T e) i. X.
• composition (x, y) may be determined so as to obtain a desired band gap by using the above equations (10) and (11).
• the band gap of the n-side cladding layer is 2. 8 8 (eV).
• the band gap E e of the B e x z n y C d ⁇ x y T e active layer is 2. 58 e V or less. From this and equation (1 1),
• FIG. 1 is an explanatory view showing a configuration of a light emitting diode (LED) as a photoelectric conversion functional element according to the present invention.
• LED light emitting diode
• FIG. 1 is an explanatory view showing a configuration of a light emitting diode (LED) as a photoelectric conversion functional element according to the present invention.
• LED light emitting diode
• the light emitting diode of this embodiment includes a p-type Mg Bet nT e cladding layer 13 and a p-type ZnTe / Mg on a p-type Z nT e substrate 11 via a Z nTe buffer layer 12.
• B e Z nT e light guide layer 14 (not necessarily required for light emitting diodes), Z n C d T e active layer 15, n-type M g S e T e / Z n T e light guide layer 6 (Not necessarily necessary for light emitting diodes), n-type Mg S e T e ZZ 11 T e cladding layer 17, Z n T e layer 18, C d S e ZZ n T e superlattice layer 19, Au electrodes 10 and 21 are formed on the front and back surfaces of the semiconductor element in which the C d S e layers 20 are sequentially stacked.
• the band gap of the p-side and n-side cladding layers 13 and 17 is larger than the band gap of the active layer 15 by 0.3 eV or more, and the light guide layers 14 and 1 adjacent to each other are included.
• the composition and the layer thickness ratio in the superlattice layer were determined so as to be larger than 0. le V by more than the pand gap of 6.
• the band gap of the p-side and n-side light guide layers 14 and 16 is such that the layer thickness ratio in the composition superlattice layer should be larger than the band gap of the active layer 15 by 0.1eV or more. Were determined.
• a p-type Z nTe single crystal having a thickness of 0.5 mm and a diameter of 2 inches and a carrier concentration of 1 ⁇ 10 18 cm ⁇ 3 was used as a growth substrate 11 when producing a light emitting diode.
• the surface of the above-mentioned Z nTe single crystal substrate 11 was lapped, followed by organic cleaning, and etching was performed for 10 minutes at 20 ° C. with a Brom-Methanol solution. Then, it was pure washed and dried, and then introduced into a molecular beam experimental apparatus.
• the substrate surface is cleaned by applying a heat treatment at 350 ° C. for 1 minute to the Z nTe single crystal substrate 11, and then the Z n T e buffer layer 1 2 on the Z n Te single crystal substrate 11. Were formed at a low temperature of 240.degree. C. and a thickness of 5 nm.
• the band gap E g 1 of this Z n Mg B e T e cladding layer 13 was 2.8 e V.
• This superlattice layer is formed by alternately stacking five layers (a total of ten layers) of a 4 n-thick Z nMg B e T e layer and a 6 M-thick Z nT e layer, and has a band gap E g 2 is 2.47 e V when J o
• the p-type Z nMg B e T e cladding layer 13 and the p-type Z n Mg B e T e / Z n T e optical guide layer 14 are doped with N (nitrogen) activated by plasma excitation as an impurity. : Controlled by type.
• an undoped Z n C d T e active layer 15 was formed to a thickness of 1 O nm on the ⁇ -type Z n Mg B e T e / Z n T e optical guide layer 14.
• the band gap E g 3 of this Z nC dT e active layer 15 was 2.13 eV.
• an n-type Mg S e 0. 568 T e 0. 432 / Z n T e light guide layer 16 (carrier concentration: 1 ⁇ 10 17 cm ⁇ 3 ) is formed on the undoped Z nC dT e active layer 15. It was formed with a thickness of 30 nm.
• This superlattice layer has a thickness of 3ML Mg S e. 568 T e 0. 432 layers and Z nT e layers with a thickness of 7 ML are alternately stacked in 5 layers (total of 10 layers), The pand gap E g 4 was 2.49 eV.
• n-type Mg S e 0568 T e 0 432 / Z nT e light guide layer 1 6 and n-type Mg S e T e 0 43 n Z nTe cladding layer 17 was controlled to 11 type by doping C 1 as an impurity.
• C d S e / Z An n T e superlattice layer 19 was formed to a thickness of 20 nm, and a C d S e layer 20 was further formed to a thickness of 5 nm thereon to form a contact layer.
• the CdSe layer 20 is controlled to n-type by doping C 1 as an impurity, and the carrier concentration is set to 1 ⁇ 10 19 cm ⁇ 3 .
• the present invention is not limited to the above-mentioned embodiment, and it can change in the range which does not deviate from the gist. is there.
• the active layer is not limited to Z n C d T e, B e Z n C d T e, Z n Mg S e T e, Mg S e T e / Z n T e superlattice, B eMg Z n T e, Z nC d S e T e etc. can be considered.
• compositions of the active layer 15, the cladding layers 13 and 17, and the light guide layers 14 and 16 are not limited to those in the above embodiment.
• the band gap E gl E g 5 force S of each layer determined using the calculation formula of the band gap corresponding to each layer 1 3 14 15 16 1 7 shown in Table 2 so as to satisfy the conditions shown in Table 3
• the composition of each layer or the layer thickness ratio of the superlattice layer may be determined.
• xl, X 2, 3 Is the composition ratio of Z n of each layer, z 1 is Z n x2 (M g 0658 B e 0. 342) Z n x2 in / ⁇ ⁇ ⁇ e ultra rated ten (M g 0. 658 B e 0.
• the p-side cladding layer 13 may be composed of a ZnMgBeTeZZnTe super lattice, or the side light guide layer may be composed of a ZnMgBeTe layer.
• the epitaxial growth method is not limited to molecular beam epitaxial growth method (MBE), and metal organic chemical vapor deposition (MOCVD) may be used.
• MBE molecular beam epitaxial growth method
• MOCVD metal organic chemical vapor deposition
• a photoelectric conversion function device having an active layer and a cladding layer satisfying a condition substantially lattice-matchable with the substrate on a p-type Z nTe single crystal substrate, wherein the band gap of the cladding layer Is less than 0.30 eV from the band gap of the active layer. Since the size is increased, the confinement efficiency of the electronic carrier can be improved, and an LED having excellent light emission characteristics can be manufactured.
• the band gap of the light guide layer is larger than the pand gap of the active layer by 0.1 l eV or more, and the pand gap of the cladding layer is larger than the band gap of the active layer by 0.30 e V or more.
• the pread gap of the light guide layer is set to be 0.2 eV or more, the confinement efficiency of the electronic carrier can be improved, and an LED having excellent light emission characteristics can be produced. Have an effect.
• n-side cladding layer and the P-side light guide layer Z n x (M g 0.658 B e 0. 342) e or Z n x (Mg 0. 658 B e 0. 342) 1-X T e / Z
• the n-side cladding layer is composed of n-Te superlattice
• the n-side light-guiding layer is the M-g-Se.
• the photoelectric conversion function element using the substrate of Z conductor single crystal as a substrate has been described, but the present invention is not limited thereto, and other II-VI compound semiconductor single crystals There is a possibility that it can be used for a photoelectric conversion function element which uses as a substrate.

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• 2002
  • 2002-03-05 JP JP2002058661A patent/JP2003258303A/ja active Pending
• 2003
  • 2003-02-26 WO PCT/JP2003/002127 patent/WO2003075365A1/ja active Application Filing

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