Abstract: A cap layer of GaN about 140 Å thick and a p-type clad layer of Mg-doped p-type AlxGa1−xN (x=0.12) about 200 Å thick are formed successively on an MQW active layer about 230 Å thick. A p-type contact layer of Mg-doped p-type AlyGa1−yN (y=0.05) about 600 Å thick is further formed thereon. These composition ratios x and y are selected to satisfy the expression “0.03 ≦0.3x≦y≦0.5x≦0.08”, so that the composition of the p-type contact layer becomes close to the composition of the p-type clad layer.

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 LED has a thin highly resistive or insulative layer formed below an electrode pad in order to divert current flow from the region below an electrode pad, which region does not contribute to light emission, to another region which does. Consequently, better current efficiency is obtained. Further, diverting current flow from the region below the electrode pad where mechanical damages are expected deters deterioration of the region. Consequently, the LED lasts longer and is a better quality product.

Abstract: An electrode for a Group III nitride compound semiconductor having p-type conduction that has a double layer structure. The first metal electrode layer comprising, for example, nickel (Ni) and the second metal electrode layer comprising, for example, gold (Au). The Ni layer is formed on the Group III nitride compound semiconductor having p-type conduction, and the Au layer is formed on the Ni layer. Heat treatment changes or reverses the distribution of the elements Ni and Au. Namely, Au is distributed deeper into the Group III nitride compound semiconductor than is Ni. As a result, the resistivity of the electrode is lowered and its ohmic characteristics are improved as well as its adhesive strength.

Abstract: An electrode for a Group III nitride compound semiconductor having p-type conduction that has a double layer structure. The first metal electrode layer comprising, for example, nickel (Ni) and the second metal electrode layer comprising, for example, gold (Au). The Ni layer is formed on the Group III nitride compound semiconductor having p-type conduction, and the Au layer is formed on the Ni layer. Heat treatment changes or reverses the distribution of the elements Ni and Au. Namely, Au is distributed deeper into the Group III nitride compound semiconductor than is Ni. As a result, the resistivity of the electrode is lowered and its ohmic characteristics are improved as well as its adhesive strength.

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 light-emitting semiconductor device (100) suitable for use in multi-color flat panel displays 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.x2 Ga.sub.1 -x.sub.2).sub.y2 In.sub.1-2 N n.sup.+ -layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Si-doped p-type (Al.sub.x1 Ga.sub.1-x1).sub.y1 In.sub.1-y1 N emission layer (5), and a Mg-doped (Al.sub.x2 Ga.sub.1-x2).sub.y2 In.sub.1-y2 N p-layer (6). The AlN layer (2) has a 500 .ANG. thickness. The GaN n.sup.+ -layer (3) is about a 2.0 .mu.m thick and has a 2.times.10.sup.18 /cm.sup.3 electron concentration. The n.sup.+ -layer (4) is about a 2.0 .mu.m in thickness and has a 2.times.10.sup.18 /cm.sup.3 electron concentration. The emission layer (5) is about 0.5 .mu.m thick. The p-layer 6 is about 1.0 .mu.m thick and has a 2.times.10.sup.17 /cm.sup.3 hole concentration. Nickel electrodes (7, 8) are connected to the p-layer (6) and n.sup.

Abstract: The present invention provides novel clathrate compounds using tetrakisphenols as host. The clathrate compounds are obtained easily and efficiently by reacting tetrakisphenols represented by the general formula [I] as host and various organic compounds such as alcohol, ether, ester, ketone, heterocyclic compounds containing nitrogen, essential oil, perfume and the like as guest under the condition of solvent-free or diluted with solvent if required. ##STR1## wherein X represents (CH.sub.2)n, n represents 0-3, and R.sup.1 and R.sup.2 represents each independently hydrogen atom, a lower alkyl group, a pheny group optionally having substituents, a halogen atom or a lower alcoxy group.The clathrate compounds specified in the present invention are useful in the technological field of selective separation, chemical stabilization, conversion to non-volatility, powder processing and the like.

Abstract: A copper alloy for electronic instruments is disclosed which comprises 2.0 to 7.0 wt. % of Sn, 1.0 to 6.0 wt. % in total amount of at least one kind of Ni, Co and Cr, o.1 to 2.0 wt. % of Si, and the remainder of Cu and unavoidable impurities, thereby further the content of O.sub.2 in unavoidable impurities being not more than 50 ppm, the content of S being not more than 20 ppm, and the average particle diameter of precipitates being not larger than 10 .mu.m. As the uses of such copper alloys, lead material for semiconductor elements and connector, socket, spring and terminal for electronic and electric instruments are claimed.

Abstract: A copper alloy is disclosed, which contains 0.1 to 3.0 wt % of Ni, 0.1 to 1.0 wt % of Ti, the ratio of Ni to Ti being 4.ltoreq.Ni/Ti thereby, 0.1 to 6.0 wt % of Sn, and 0.005 to 3.0 wt % in total of one or more elements selected from the group consisting of Zn, Mn, Mg, Ca, RE, B, Sb, Te, Si, Co, Fe, Zr, Ag, Mm and Al, and consists of the remainder of Cu and the inevitable impurities. The method for the manufacture of the alloy is characterized in that, after copper alloy ingot was maintained and homogenized for 0.5 to 15 hours at 750.degree. to 960.degree. C. prior to rolling, the hot rolling is carried out starting from a temperature of 700.degree. to 880.degree. C. and the cooling is made immediately after the end of rolling.

Abstract: Composite oxyalkoxides and their derivatives are novel organometallic compounds which give alkaline earth metal titanates such as barium titanate or strontium titanate by hydrolysis or thermal decomposition. The oxyalkoxides are synthesized by the reaction between an alkoxytitanium and an alkaline earth metal hydroxide, and their derivatives are synthesized by the reaction between the composite oxyalkoxide and a chelating agent.