Radiation-emitting optoelectronic device

Abstract

A radiation-emitting optoelectronic device is provided. The radiation-emitting optoelectronic device includes a semiconductor chip that, when the device is in operation, emits primary radiation of a wavelength of between 600 nm and 1000 nm. A conversion element includes a conversion material comprising ions of one or more metals selected from a group comprising La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Cr, Pb and Mg. The conversion material converts the primary radiation emitted by the semiconductor chip virtually completely into secondary radiation of a wavelength of between 1000 nm and 6000 nm.

Claims

1. A radiation-emitting optoelectronic device comprising: a semiconductor chip configured to emit primary radiation of a wavelength of between 800 nm and 1000 nm when the device is in operation; and a conversion element that comprises a conversion material comprising a host material and ions of at least one metal selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Cr, wherein the host material with the ions form a compound of a formula, the formula being one of (A,B).sub.3X.sub.5O.sub.12, (A,B).sub.2X*.sub.3O.sub.12, C.sub.3(A,B).sub.2Z.sub.3O.sub.12, C.sub.3(A,B).sub.2Z*.sub.6O.sub.24 and (A,B).sub.3X.sub.5N.sub.8, wherein: A=Fe.sup.3+, Cr.sup.3+, V.sup.3+, Ti.sup.3+, Sc.sup.3+, Lu.sup.3+ or Y.sup.3+; B is a trivalent cation of a metal selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Cr; C=Mg.sup.2+, Fe.sup.2+, Mn.sup.2+, Pb.sup.2+ or Ca.sup.2+; X=Al.sup.3+ or B.sup.3+; X*=W.sup.6+; Z=Si.sup.4+ or Ti.sup.4+; and Z*=W.sup.6+, and wherein the conversion material is configured to convert the primary radiation emitted by the semiconductor chip with a conversion over 95% into secondary radiation of a wavelength of between woo nm and 6000 nm when the device is in operation.

2. The radiation-emitting optoelectronic device according to claim 1, wherein B=Ho.sup.3+ or Tm.sup.3+.

3. The radiation-emitting optoelectronic device according to claim 1, wherein the conversion element comprises a sensitizer that is excited by the emitted primary radiation when the device is in operation, wherein an exciton is excited from a basic state to a higher energy level, the exciton is transferred to the conversion material and the conversion material emits a secondary radiation of a wavelength of between 1000 nm and 6000 nm.

4. The radiation-emitting optoelectronic device according to claim 1, wherein the conversion element is part of a potting compound of the semiconductor chip.

5. The radiation-emitting optoelectronic device according to claim 1, wherein the conversion element forms a potting compound.

6. The radiation-emitting optoelectronic device according to claim 1, wherein the conversion element takes the form of a layer that is in direct contact with the semiconductor chip.

7. A gas sensor comprising: a radiation-emitting optoelectronic device according to claim 1, a detector configured to detect radiation; and a gas chamber arranged between the radiation-emitting optoelectronic device and the detector, wherein the radiation detected by the detector is at least one of the primary radiation and secondary radiation emitted by the radiation-emitting optoelectronic device and then passed through the gas chamber.

8. A method of producing a radiation-emitting optoelectronic device, the method comprising: providing a semiconductor chip configured to emit primary radiation of a wavelength of between 800 nm and 1000 nm; and applying a conversion element over the semiconductor chip, the conversion element comprising a conversion material comprising a host material and ions of at least one metal selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Cr, wherein the host material with the ions form a compound of a formula, the formula being one of (A,B).sub.3X.sub.5O.sub.12, (A,B).sub.2X*.sub.3O.sub.12, C.sub.3(A,B).sub.2Z.sub.3O.sub.12, C.sub.3(A,B).sub.2Z*.sub.6O.sub.24 and (A,B).sub.3X.sub.5N.sub.8, wherein: A=Fe.sup.3+, Cr.sup.3+, V.sup.3+, Ti.sup.3+, Sc.sup.3+, Lu.sup.3+ or Y.sup.3+; B is a trivalent cation of a metal selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Cr; C=Mg.sup.2+, Fe.sup.2+, Mn.sup.2+, Pb.sup.2+ or Ca.sup.2+; X=Al.sup.3+ or B.sup.3+; X*=W.sup.6+; Z=Si.sup.4+ or Ti.sup.4+; and Z*=W.sup.6+, and wherein the conversion material configured to convert the primary radiation emitted by the semiconductor chip with a conversion over 95% into secondary radiation of a wavelength of between 1000 nm and 6000 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments and further developments of the invention are revealed by the exemplary embodiments described below in connection with the figures.

(2) FIGS. 1 to 3 show schematic side views of various embodiments of radiation-emitting optoelectronic devices.

(3) Identical, similar or identically acting elements are provided with identical reference numerals in the figures. The figures and the size ratios of the elements illustrated in the figures relative to one another are not to be regarded as being to scale. Rather, individual elements may be illustrated on an exaggeratedly large scale for greater ease of depiction and/or better comprehension.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(4) The exemplary embodiment shown in FIG. 1 of a radiation-emitting optoelectronic device 1 comprises a semiconductor chip 2, a back surface contact 15, a front surface contact 16 and an active epitaxial layer sequence 9, wherein the active epitaxial layer sequence 9 emits primary radiation of a wavelength of between 600 nm and 1000 nm when in operation.

(5) The semiconductor chip 2 is mounted by means of an electrically conductive bonding agent with the back surface contact 15 on a first terminal 4. The electrically conductive bonding agent used is, for example, a metallic solder or an adhesive. The front surface contact 16 is bonded to a second electrical terminal 5 by means of a bonding wire 17.

(6) In the exemplary embodiment shown in FIG. 1, the first and second electrical terminals 4, 5 are embedded in an opaque, for example, prefabricated basic package 10 with a recess 11. Prefabricated should be understood to mean that the basic package 10 has already been fully formed on the terminals 4, 5, for example, by means of injection molding before the semiconductor chip 2 is mounted on the terminal 4. The basic package 10 comprises, for example, an opaque plastics material and the recess 11 is configured in terms of its shape as a reflector 18 for the primary radiation and secondary radiation, wherein the reflection may optionally be achieved by a suitable coating of the inner walls of the recess 11. Such basic packages 10 are used in particular for surface-mountable light-emitting diodes. They are applied prior to mounting of the semiconductor chip 2 to a conductor tape comprising the electrical terminals 4, 5, for example, by means of injection molding and/or transfer molding.

(7) In the exemplary embodiment of FIG. 1, the conversion element 6 takes the form of a potting compound and fills the recess 11, as shown in FIG. 1. The conversion element comprises a conversion material and a matrix material, in which the conversion material is embedded. The matrix material, for example, of an acrylate. The conversion material consists of a host material and Tm.sup.3+ ions, wherein the host material with the Tm.sup.3+ ions forms a compound of the formula (Y,Tm).sub.3Al.sub.5O.sub.12. The primary radiation emitted by the semiconductor chip 2 is converted at least in part by the conversion material into secondary radiation of a wavelength of between 1000 nm and 5000 nm.

(8) A further exemplary embodiment of a radiation-emitting optoelectronic device described here is described in connection with FIG. 2. In the exemplary embodiment of FIG. 2, the conversion element 6 is configured as a layer. The conversion element consists of a silica glass, in which converter particles of (Lu,Ho).sub.3Al.sub.5O.sub.12 are distributed homogeneously as conversion material.

(9) The conversion element 6 is applied directly onto the semiconductor chip 2. The semiconductor chip 2 and at least sub-regions of the electrical terminals 4, 5 are enclosed by a radiation-transmissive enclosure 13, which does not bring about any change in wavelength or frequency in the radiation passing through the conversion element 6. The radiation-transmissive enclosure may, for example, consist of at least one of the following materials and/or contain at least one of the following materials: silicone, epoxide, polyurethane or glass.

(10) In the exemplary embodiment shown in FIG. 3, the first and second electrical terminals 4, 5 are embedded in an opaque, possibly prefabricated basic package 10 with a recess 11. As is apparent from FIG. 3, the free surfaces of the semiconductor chip 2 and sub-regions of the electrical terminals 4 and 5 are surrounded at least in part and/or directly by a radiation-transmissive enclosure 12. This radiation-transmissive enclosure 12 does not cause any change in wavelength in the primary radiation emitted by the semiconductor chip 2. The radiation-transmissive enclosure 12 consists, for example, of one of the radiation-transmissive materials already mentioned above or contains at least one of these materials. Furthermore, the recess 11 in this embodiment may be filled with a gas.

(11) The recess 11 of FIG. 3 is covered by a conversion element 6 consisting of a matrix material and a conversion material, wherein the conversion element 6 is, for example, a separately produced cover plate 6 mounted on the basic package 10. Examples of suitable materials which may be considered for the conversion element 6 include a ceramic material in which (Y,Ho).sub.3Al.sub.5N.sub.8 is homogeneously distributed as a conversion material.

(12) For better outcoupling of the light out of the conversion element 6 of FIG. 3, a lenticular cover 21 (shown in broken lines) may be provided on a side face of the device at which radiation exits, the lenticular cover reducing the total reflection of the radiation within the conversion element 6. This lenticular cover 21 may in particular consist of a radiation-transmissive plastics material or a glass and, for example, be adhesively bonded to the conversion element 6 or configured directly as a component of the conversion element 6.

(13) The description made with reference to exemplary embodiments does not restrict the invention to these embodiments. Rather, the invention encompasses any novel feature and any combination of features, including in particular any combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the claims or exemplary embodiments.