Abstract: The present invention provides a method for producing a Group III nitride compound semiconductor, which method permits only minimal reaction of the semiconductor with a hetero-substrate during epitaxial growth and induces no cracks in the Group III nitride compound semiconductor even when the semiconductor is cooled to room temperature. The method includes a buffer layer formation step for forming a gas-etchable buffer layer on the hetero-substrate, and a semiconductor formation step for epitaxially growing the Group III nitride compound semiconductor on the buffer layer through a vapor phase growth method, wherein at least a portion of the buffer layer is gas-etched during or after the semiconductor formation step.

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1−xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1−xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1−xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semic

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1−xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1−xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1−xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semic

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1-xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1-xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1-xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semiconductor (AlxGa1-x

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1−xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1−xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1−xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semic

Abstract: A light-emitting semiconductor device (10) consecutively includes a sapphire substrate (1), an AlN buffer layer (2), a silicon (Si) doped GaN n+-layer (3) of high carrier (n-type) concentration, a Si-doped (Alx3Ga1-x3)y3In1-y3N n+-layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Si-doped (Alx2Ga1-x2)y2In1-y2N emission layer (5), and a Mg-doped (Alx1Ga1-x1)y1In1-y1N p-layer (6). The AlN layer (2) has a 500 Å thickness. The GaN n+-layer (3) has about a 2.0 &mgr;m thickness and a 2×1018/cm3 electron concentration. The n+-layer (4) has about a 2.0 &mgr;m thickness and a 2×1018/cm3 electron concentration. The emission layer (5) has about a 0.5 &mgr;m thickness. The p-layer 6 has about a 1.0 &mgr;m thickness and a 2×1017/cm3 hole concentration. Nickel electrodes (7, 8) are connected to the p-layer (6) and n+-layer (4), respectively. A groove (9) electrically insulates the electrodes (7, 8).

Abstract: A light-emitting semiconductor device (10) consecutively includes a sapphire substrate (1), an AlN buffer layer (2), a silicon (Si) doped GaN n+-layer (3) of high carrier (n-type) concentration, a Si-doped (Alx3Ga1−x3)y3In1−y3N n+-layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Si-doped (Alx2Ga1−x2)y2In1−y2N emission layer (5), and a Mg-doped (Alx1Ga1−x1)y1In1−y1N p-layer (6). The AlN layer (2) has a 500 Å thickness. The GaN n+-layer (3) has about a 2.0 &mgr;m thickness and a 2×1018/cm3 electron concentration. The n+-layer (4) has about a 2.0 &mgr;m thickness and a 2×1018/cm3 electron concentration. The emission layer (5) has about a 0.5 &mgr;m thickness. The p-layer 6 has about a 1.0 &mgr;m thickness and a 2×1017/cm3 hole concentration. Nickel electrodes (7, 8) are connected to the p-layer (6) and n+-layer (4), respectively. A groove (9) electrically insulates the electrodes (7, 8).

Abstract: A semiconductor device having an n-type layer of gallium nitride that is doped with silicon and has a resistively ranging from 3×10−1 &OHgr;cm to 8×10−3 &OHgr;cm or a carrier concentration ranging from 6×1016/cm3 to 3×1018/cm3.

Abstract: An effervescent granular preparation for keeping cut flower freshness includes an azole-substituted cyclopentanol derivative represented by formula (I) (set forth below) and 2-bromo-2-nitro-1, 3-propanediol as effective components and to a process for producing the same. The effervescent granular preparation is produced by granulation of a mixture containing at least one of glucose, D-mannitol and sucrose as an excipient by incorporating an organic acid such as citric acid or malic acid and a hydrogen carbonate such as sodium hydrogen carbonate. ##STR1## wherein A represents a nitrogen atom or a CH group, R.sup.1 and R.sup.2 represent each independently a hydrogen or a C.sub.1 -C.sub.3 alkyl group, and X represents a hydrogen atom or a halogen atom.

Abstract: A light-emitting semiconductor device (10) consecutively includes a sapphire substrate (1), an AlN buffer layer (2), a silicon (Si) doped GaN n.sup.+ -layer (3) of high carrier (n-type) concentration, a Si-doped (Al.sub.x3 Ga.sub.1-x3).sub.y3 In.sub.1-y3 N n.sup.+ -layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Si-doped (Al.sub.x2 Ga.sub.1-x2).sub.y2 In.sub.1-y2 N emission layer (5), and a Mg-doped (Al.sub.x1 Ga.sub.1-x1).sub.y1 In.sub.1-y1 N p-layer (6). The AlN layer (2)--is 500 .ANG. in thickness. The GaN N.sup.+ -layer (3) is about 2.0 .mu.m in thickness and has an electron concentration of about 2.times.10.sup.18 /cm.sup.3. The n.sup.+ -layer (4) is about 2.0 .mu.m in thickness and has an electron concentration of about 2.times.10.sup.18 /cn.sup.3. The emission layer (5) is about 0.5 .mu.m in thickness. The p-layer 6 is about 1.0 .mu.m in thickness and has a hole concentration of about 2.times.10.sup.17 /cm.sup.3. Nickel electrodes (7, 8) are connected to the p-layer (6) and n.sup.

Abstract: A probe for measuring a depth of a periodontal pocket includes an emitting device for emitting, from a position at a distance from the periodontal pocket, a light beam toward the periodontal pocket, a receiving device for receiving, at a position at another distance from the periodontal pocket, the light beam after being reflected on a bottom of the periodontal pocket, and an analyzing device for displaying the depth of the periodontal pocket after a calculation thereof on the basis of an analysis of the light beam received at the receiving device.

Abstract: A light-emitting diode or laser diode is provided which uses a Group III nitride compound semiconductor satisfying the formula (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y N, inclusive of 0.ltoreq.x.ltoreq.1, and 0.ltoreq.y.ltoreq.1. A double hetero-junction structure is provided which sandwiches an active layer between layers having wider band gaps than the active layer. The diode has a multi-layer structure which has either a reflecting layer to reflect emission light or a reflection inhibiting layer. The emission light of the diode exits the diode in a direction perpendicular to the double hetero-junction structure. Light emitted in a direction opposite to the light outlet is reflected by the reflecting film toward the direction of the light outlet. Further, the reflection inhibiting film, disposed at or near the light outlet, helps the release of exiting light by minimizing or preventing reflection. As a result, light can be efficiently emitted by the light-generating diode.

Abstract: A light-emitting semiconductor device using a gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) having an i.sub.L -layer of insulating gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) containing a low concentration of p-type impurities. An i.sub.H -layer of insulating gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) containing a high concentration of p-type impurities is adjacent to the i.sub.L -layer. An n-layer of n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) of low carrier concentration is adjacent to the i.sub.L -layer. An n.sup.+ -layer of n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N, inclusive of x=0) of high carrier concentration doped with n-type impurities is adjacent to the n-layer.

Abstract: A light-emitting semiconductor device a sapphire substrate (1), an AlN buffer layer (2), a silicon (Si) doped GaN n.sup.+ -layer (3) of high carrier (n-type) concentration, a Si-doped (Al.sub.x2 Ga.sub.1-x2).sub.y2 In.sub.1-y2 N n.sup.+ -layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Mg doped ((Al.sub.x1 Ga.sub.1-x1).sub.y2 In.sub.1-y2 N n.sup.+ -layer (5), and a Mg doped (Al.sub.x2 Ga.sub.1-x2).sub.y2 In.sub.1-y2 N n.sup.+ -layer (6). The AlN layer (2) has a 500 .ANG. thickness. The GaN n.sup.+ -layer (3) has about a 2.0 .mu.m thickness and a 2.times.10.sup.18 /cm.sup.3 electron concentration. The n.sup.+ -layer (4) has about a 2.0 .mu.m thickness and a 2.times.10.sup.18 /cm.sup.3 electron concentration. A double i-layer structure includes the emission layer (5) and the i-layer (6). The emission layer (5) has about a 0.5 .mu.m thickness, and the i-layer (6) has about a 0.5 .mu.m thickness. Parts of the emission layer (5) and the i-layer (6) are p-type regions (50, 60).

Abstract: A light-emitting semiconductor device includes a sapphire substrate whose main surface orientation is tilted by 1 to 4 degrees from its axis "a" <1120>, and layers epitaxially formed thereon. Tilting the surface orientation of the sapphire substrate enables uniform doping of a p-type impurity into the layers epitaxially grown thereon. As a result, the luminous intensity of the light-emitting semiconductor device is improved.

Abstract: A gallium nitride group compound semiconductor laser diode (10) satisfying the formula (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y N, inclusive of 0.ltoreq.x.ltoreq.1 and 0.ltoreq.y.ltoreq.1 comprises by a double hetero-junction structure sandwiching an active layer (5) between layers (4, 6) having wider band gaps than the active layer (5). The active layer (5) may comprise magnesium (Mg) doped p-type conductive gallium nitride group compound semiconductor satisfying the formula (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y N, inclusive of 0.ltoreq.x.ltoreq.1 and 0.ltoreq.y.ltoreq.1 . In another embodiment, the active layer (5) is doped with silicon (Si).

Abstract: Disclosed herein are N-substituted-3-(nitrogen-containing 5-membered ring)benzenesulfonamide derivatives of the formula (I): ##STR1## R.sup.1 is H, Cl, C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.4 alkoxycarbonyl; Z is CH or N; X.sup.1 is C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 alkoxyl or Cl; and X.sup.2 is C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.3 alkoxyl, a process for the preparation thereof, and herbicidal compositions containing the N-substituted-3-(nitrogen-containing 5-membered ring)benzenesulfonamide derivatives as active ingredients.

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) in which the n-layer of n-type gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N) is of double-layer structure including an n-layer of low carrier concentration and an n.sup.+ -layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (Al.sub.x Ga.sub.1-x N); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an i.sub.L -layer of low impurity concentration containing p-type impurities in comparatively low concentration and an i.sub.

Abstract: Disclosed herein are N-substituted-3-(nitrogen-containing 5-membered ring)benzenesulfonamide derivatives of the formula (I): ##STR1## R.sup.1 is H, Cl, C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.4 alkoxycarbonyl; Z is CH or N; X.sup.1 is C.sub.1 -C.sub.3 is alkyl, C.sub.1 -C.sub.3 alkoxyl or Cl; and X.sup.2 is C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.3 alkoxyl, a process for the preparation thereof, and herbicidal compositions containing the N-substituted-3-(nitrogen-containing 5-membered ring)benzenesulfonamide derivatives as active ingredients.

Abstract: Disclosed herein are N-substituted-3-(substituted hydrazino)benzenesulfonamide derivatives of the formula (I): ##STR1## wherein R.sup.1 and CF.sub.3, COOH or CCl=CClCOOH, R.sup.2 is H, Cl, C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.4 alkoxycarbonyl; Z is CH or N; X.sup.1 is C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 alkoxyl or Cl; and X.sup.2 is C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.3 alkoxyl, a process for the preparation thereof, and herbicidal compositions containing the N-substituted-3-(substituted hydrazino)benzenesulfonamide derivatives as active ingredients.