US4675709A
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Quantized layered structures with adjusted indirect bandgap transitions
Assignee: Xerox Corp
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Filing: 1986-01-21
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Granted: 1987-06-23
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Expires: 2006-01-21
Abstract
Abstract A semiconductor quantized layered structure comprising first and second different semiconductor materials comprising compound semiconductors from both the Group III and Group V elements and forming a plurality of alternate layers, each interfaced to its adjacent layer in a semiconductor homojunction or heterojunction. The bottom of the conduction bands of the first and second materials are at different energy levels and the tops of the valence bands of the first and second materials are at different energy levels. The bottoms of the conduction bands of the first and second materials form a plurality of serially arranged potential wells and barriers due to differences in the band structures of the different materials forming alternate layers and the interfacing of the layers forming heterojunctions so that the thinness of the layers will spatially localize electrons to obtain quantized electron states in one dimension transverse to the longitudinal extent of said layers. The invention is characterized in that the first material is an indirect bandgap material and optimized luminescence efficiency of the first material is achieved by adjusting the thickness of the layers comprising the first material to be less than the mean free path of an electron in the first material in the absence of the second material. Three dimensional quantized electron states may be provided in certain layers of the quantized layered structure with the incorporation of an impurity, such as, a donor or acceptor impurity or an isoelectronic impurity forming isoelectronic centers (IEC) in the indirect bandgap semiconductor material. Such an incorporation may be in each layer of the first and second materials or only in the alternate layers of the lower indirect bandgap material. Alternatively, the impurity may be in a predetermined periodic alternate of layers of the same indirect bandgap material, e.g., in one layer out of three, in alternate layers of a plurality of layers or in every n th layer or every n th group of layers where n may be any integer.
Inventors
- 👤 Donald R. Scifres
- 👤 Robert D. Burnham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:39
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/811; H10H20/812; B; B82; B82Y; B82Y20/00; H01; H01S; H01S5/00; H01S5/30; H01S5/34; H10D; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8164; Y; Y10; Y10S; Y10S148/00; Y10S148/023; Y10S148/04; Y10S148/072; Y10S148/119; Y10S148/16
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
262 words
A semiconductor quantized layered structure comprising first and second different semiconductor materials comprising compound semiconductors from both the Group III and Group V elements and forming a plurality of alternate layers, each interfaced to its adjacent layer in a semiconductor heterojunction, the bottom of the conduction bands of said first and second materials being at different energy levels and the tops of the valence bands of said first and second materials being at different energy levels, the bottoms of said conduction bands of said first and second materials forming a plurality of serially arranged potential wells and barriers due to differences in the band structures of said different materials forming said alternate layers and the interfacing of said layers in said heretojunctions so that the thinness of said layers will spatially localize electrons to obtain quantized electron states in one dimension transverse to the longitudinal extent of said layers, characterized in that said first material is an indirect bandgap material, said first material having optimized luminescence efficiency achieved by adjusting the thickness of said layers comprising said first material to be less than the mean free path of an electron in said first material in the absence of said second material, said first material is an alloy composition with the compositional alloy adjusted to be near its bulk direct/indirect transition, the layer or layers of said first and second materials are doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 2
Dependent Claim
262 words
A semiconductor quantized layered structure comprising first and second different semiconductor materials comprising compound semiconductors from both the Group III and Group V elements and forming a plurality of alternate layers, each interfaced to its adjacent layer in a semiconductor heterojunction, the bottom of the conduction bands of said first and second materials being at different energy levels and the tops of the valence bands of said first and second materials being at different energy levels, the bottoms of said conduction bands of said first and second materials forming a plurality of serially arranged potential wells and barriers due to differences in the band structures of said different materials forming said alternate layers and the interfacing of said layers in said heretojunctions so that the thinness of said layers will spatially localize electrons to obtain quantized electron states in one dimension transverse to the longitudinal extent of said layers, characterized in that said first material is an indirect bandgap material, said first material having optimized luminescence efficiency achieved by adjusting the thickness of said layers comprising said first material to be less than the mean free path of an electron in said first material in the absence of said second material, said first material is an alloy composition with the compositional alloy adjusted to be near its bulk direct/indirect transition, the layer or layers of said first and second materials are doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 3
Dependent Claim
53 words
The semiconductor quantized layered structure of claim 1 wherein the layer or layers of said first material are doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in said first material in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 4
Dependent Claim
51 words
The semiconductor quantized layered structure of claim 1 wherein the layer or layers of said first and second materials are doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 5
Dependent Claim
49 words
The semiconductor quantized layered structure of claim 1 wherein the layer or layers of said first material are doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 6
Dependent Claim
20 words
The semiconductor quantized layered structure of any one of the claims 1 through 4 wherein said isoelectronic impurity is nitrogen.
Claim 7
Dependent Claim
46 words
The semiconductor quantized layered structure of any one of the claims 1 through 4 wherein the thickness of said first material layers is in the range of 5 Å-20 Å and the thickness of said second material layers is in the range of 10 Å-100 Å.
Claim 8
Dependent Claim
30 words
The semiconductor quantized layered structure of any one of the claims 1 through 4 wherein the thickness of any of said layers is in the range of 5 Å-50 Å.
Claim 9
Dependent Claim
33 words
The semiconductor quantized layered structure of any one of the claims 1 through 4 wherein there is only a single layer of said first material and sandwiched between layers of said second material.
Claim 10
Dependent Claim
31 words
The semiconductor quantized layered structure of any one of the claims 1 through 4 wherein there are several layers of said first material alternating with the layers of said second material.
Claim 11
Dependent Claim
37 words
The semiconductor quantized layered structures of any one of the claims 1 through 4 wherein said layers are sandwiched by cladding layers having a wider bandgap than the bandgap of either of said first and second materials.
Claim 12
Dependent Claim
202 words
A semiconductor quantized layered structure comprising first and second different semiconductor materials comprising compound semiconductors from both the Group III and Group V elements and forming a plurality of alternate layers, each interfaced to its adjacent layer in a semiconductor heterojunction, the bottom of the conduction bands of said first and second materials being at different energy levels and the tops of the valence bands of said first and second materials being at different energy levels, the bottoms of said conduction bands of said first and second materials forming a plurality of serially arranged potential wells and barriers due to differences in the band structures of said different materials forming said alternate layers and the interfacing of said layers in said heterjunctions so that the thinness of said layers will spatially localize electrons to obtain quantized electron states in one dimension transverse to the longitudinal extent of said layers, characterized in that said first material is an indirect bandgap material, the layer or layers of said first and second materials being doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 13
Dependent Claim
202 words
A semiconductor quantized layered structure comprising first and second different semiconductor materials comprising compound semiconductors from both the Group III and Group V elements and forming a plurality of alternate layers, each interfaced to its adjacent layer in a semiconductor heterojunction, the bottom of the conduction bands of said first and second materials being at different energy levels and the tops of the valence bands of said first and second materials being at different energy levels, the bottoms of said conduction bands of said first and second materials forming a plurality of serially arranged potential wells and barriers due to differences in the band structures of said different materials forming said alternate layers and the interfacing of said layers in said heterjunctions so that the thinness of said layers will spatially localize electrons to obtain quantized electron states in one dimension transverse to the longitudinal extent of said layers, characterized in that said first material is an indirect bandgap material, the layer or layers of said first and second materials being doped with an isoelectronic impurity to form isoelectronic centers that quantize electron states in three dimensions whereby electrons are localized in all directions relative to spatial regions of said formed wells.
Claim 14
Dependent Claim
14 words
The semiconductor quantized layered structure of claim 11 wherein said isoelectronic impurity is nitrogen.
Claim 15
Dependent Claim
50 words
The semiconductor quantized layered structure of claim 11 wherein said first material has optimized luminescence efficiency achieved by adjusting the thickness of said layers comprising said first material to be less than the mean free path of an electron in said first material in the absence of said second material.
Claim 16
Dependent Claim
28 words
The semiconductor quantized layered structure of claim 11 wherein only the layer or layers of said first material being doped with an isoelectronic impurity to form isoelectronic centers.
Claim 17
Dependent Claim
45 words
The semiconductor quantized layered structure of any one of the claims 11 through 14 wherein the thickness of said first material layers is in the range of 5 Å-20 Å and the thickness of said second material layers is in the range of 10 Å-100Å.
Claim 18
Dependent Claim
27 words
The semiconductor quantized layered structure of any one of the claims 11 through 14 wherein the thickness of said layers is in the range of 5 Å-50Å.
Claim 19
Dependent Claim
33 words
The semiconductor quantized layered structure of any one of the claims 11 through 14 wherein there is only a single layer of said first material and sandwiched between layers of said second material.
Claim 20
Dependent Claim
31 words
The semiconductor quantized layered structure of any one of the claims 11 through 14 wherein there are several layers of said first material alternating with the layers of said second material.
Claim 21
Dependent Claim
37 words
The semiconductor quantized layered structures of any one of the claims 11 through 14 wherein said layers are sandwiched by cladding layers having a wider bandgap than the bandgap of either of said first and second materials.
Claim 22
Dependent Claim
115 words
A semiconductor quantized layered structure for incorporation into a light emitting device comprising a central region of alternating thin congruent layers of indirect bandgap material, said indirect bandgap material composed of Group III and Group V elements, one group of said layers being doped with an impurity to form alternating layers to spatially localize carriers, said layers each having a thickness in the range of approximately 5 Å to 50 Å to provide quantum size effect to improve radiative recombination effects in said structure, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type.
Claim 23
Dependent Claim
115 words
A semiconductor quantized layered structure for incorporation into a light emitting device comprising a central region of alternating thin congruent layers of indirect bandgap material, said indirect bandgap material composed of Group III and Group V elements, one group of said layers being doped with an impurity to form alternating layers to spatially localize carriers, said layers each having a thickness in the range of approximately 5 Å to 50 Å to provide quantum size effect to improve radiative recombination effects in said structure, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type.
Claim 24
Dependent Claim
26 words
The semiconductor quantized layered structure of claim 20 wherein said first conductivity type contains an acceptor impurity and said second conductivity type contains a donor impurity.
Claim 25
Dependent Claim
15 words
The semiconductor quantized layered structure of claim 20 wherein said impurity is a donor impurity.
Claim 26
Dependent Claim
25 words
The semiconductor quantized layered structure of claim 22 wherein said donor is selected from the group consisting of Si, Se, Te, Sn, S or Ge.
Claim 27
Dependent Claim
15 words
The semiconductor quantized layered structure of claim 20 wherein said impurity is an acceptor impurity.
Claim 28
Dependent Claim
26 words
The semiconductor quantized layered structure of claim 24 wherein said acceptor impurity is selected from the group consisting of Zn, Cd, Mg, Be, Si or Ge.
Claim 29
Dependent Claim
42 words
The semiconductor quantized layered structure of claim 20 wherein said indirect bandgap material has optimized luminescence efficiency achieved by adjustng the thickness of said layers comprising said material to be less than the mean free path of an electron in said material.
Claim 30
Dependent Claim
29 words
The semiconductor quantized layered structure of claim 20 wherein said indirect bandgap material is an alloy composition with the compositional alloy adjusted to be near its bulk direct/indirect transition.
Claim 31
Dependent Claim
30 words
The semiconductor quantized layered structure of claim 20 wherein said central region is bounded by wider bandgap semiconductor cladding layers comprising said material of said first and second conductivity type.
Claim 32
Dependent Claim
52 words
A semiconductor quantized layered structure comprising a central region having one layer of indirect bandgap material with adjacent layers of wider bandgap compared to said layer, an isoelectronic impurity in said layer to provide isoelectronic traps therein to spatially localize carriers, said layer being sufficiently thin to a provide quantum size effect.
Claim 33
Dependent Claim
52 words
A semiconductor quantized layered structure comprising a central region having one layer of indirect bandgap material with adjacent layers of wider bandgap compared to said layer, an isoelectronic impurity in said layer to provide isoelectronic traps therein to spatially localize carriers, said layer being sufficiently thin to a provide quantum size effect.
Claim 34
Dependent Claim
92 words
A semiconductor quantized layered structure comprising a central region having at least one layer of indirect bandgap material with adjacent layers of wider bandgap compared to said one layer, said one layer provided with an isoelectronic impurity to spatially localize carriers, said one layer being sufficiently thin to provide a quantum size effect, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 35
Dependent Claim
92 words
A semiconductor quantized layered structure comprising a central region having at least one layer of indirect bandgap material with adjacent layers of wider bandgap compared to said one layer, said one layer provided with an isoelectronic impurity to spatially localize carriers, said one layer being sufficiently thin to provide a quantum size effect, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 36
Dependent Claim
120 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers being of a different bandgap than the other group of said layers to form alternating layers of narrow and wide indirect bandgap material, one of said groups of alternating layers also containing an isoelectronic impurity to spatially localize carriers, said layers being sufficiently thin, to provide quantum size effect to improve radiative recombination effects in said structure, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 37
Dependent Claim
120 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers being of a different bandgap than the other group of said layers to form alternating layers of narrow and wide indirect bandgap material, one of said groups of alternating layers also containing an isoelectronic impurity to spatially localize carriers, said layers being sufficiently thin, to provide quantum size effect to improve radiative recombination effects in said structure, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 38
Dependent Claim
21 words
The semiconductor quantized layered structure of claim 31 wherein all of said layers contain an isoelectronic impurity to spatially localize carriers.
Claim 39
Dependent Claim
98 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers being doped with a shallow impurity, said one group of alternating layers also containing an isoelectronic impurity the combination of which spatially localize carriers, said layers being sufficiently thin, to provide a quantum size effect, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 40
Dependent Claim
98 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers being doped with a shallow impurity, said one group of alternating layers also containing an isoelectronic impurity the combination of which spatially localize carriers, said layers being sufficiently thin, to provide a quantum size effect, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 41
Dependent Claim
39 words
The semiconductor quantized layered structure of claim 33 wherein said one group of said alternating layers being of a different bandgap than the other grop of said layers to form alternating layers of narrow and wide indirect bandgap material.
Claim 42
Dependent Claim
97 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers being doped with a shallow impurity and a second group of second alternating layer provided with an isoelectronic impurity to spatially localize carriers, said layers being sufficiently thin, to provide a quantum size effect, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 43
Dependent Claim
97 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers being doped with a shallow impurity and a second group of second alternating layer provided with an isoelectronic impurity to spatially localize carriers, said layers being sufficiently thin, to provide a quantum size effect, said central region being bounded on one side by a material of a first conductivity type and being bounded on the other side by a material of a second conductivity type to form a p-n junction across said region.
Claim 44
Dependent Claim
39 words
The semiconductor quantized layered structure of claim 35 wherein said one group of said alternating layers being of a different bandgap than the other group of said layers to form alternating layers of narrow and wide indirect bandgap material.
Claim 45
Dependent Claim
89 words
A semiconductord quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers provided with an isoelectronic impurity, said layers being sufficiently thin to provide a quantum size effect, a first set of said congruent layers being doped with an impurity of a first conductivity type and a second set of said congruent layers adjacent to said first set being doped with an impurity of a second conductivity type to form a p-n junction in said central region.
Claim 46
Dependent Claim
89 words
A semiconductord quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, one group of said alternating layers provided with an isoelectronic impurity, said layers being sufficiently thin to provide a quantum size effect, a first set of said congruent layers being doped with an impurity of a first conductivity type and a second set of said congruent layers adjacent to said first set being doped with an impurity of a second conductivity type to form a p-n junction in said central region.
Claim 47
Dependent Claim
39 words
The semiconductor quantized layered structure of claim 37 wherein said one group of said alternating layers being of a different bandgap than the other group of said layers to form alternating layers of narrow and wide indirect bandgap material.
Claim 48
Dependent Claim
57 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, said indirect bandgap material composed of Group III and Group V elements, one group of said layers provided with an isoelectronic impurity to spatially localize carriers, each of said layers being sufficiently thin to provide a quantum size effect.
Claim 49
Dependent Claim
57 words
A semiconductor quantized layered structure comprising a central region of alternating thin congruent layers of indirect bandgap material, said indirect bandgap material composed of Group III and Group V elements, one group of said layers provided with an isoelectronic impurity to spatially localize carriers, each of said layers being sufficiently thin to provide a quantum size effect.
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