Abstract: According to one embodiment, a nitride semiconductor element includes: a stacked body; and a functional layer. The stacked body includes a first GaN layer, a first layer, and a second GaN layer. The first GaN layer includes a first protrusion. The first layer is provided on the first GaN layer and contains at least one of Si and Mg. The second GaN layer is provided on the first layer and includes a second protrusion. Length of bottom of the second protrusion is shorter than length of bottom of the first protrusion. A functional layer is provided on the stacked body and includes a nitride semiconductor.

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting part, and a p-side electrode. The light emitting part is provided between the n-type and the p-type semiconductor layers, and includes a plurality of barrier layers and a plurality of well layers. The p-side electrode contacts the p-type semiconductor layer. The p-type semiconductor layer includes first, second, third, and fourth p-type layers. The first p-type layer contacts the p-side electrode. The second p-type layer contacts the light emitting part. The third p-type layer is provided between the first p-type layer and the second p-type layer. The fourth p-type layer is provided between the second p-type layer and the third p-type layer. The second p-type layer contains Al and contains a p-type impurity in a lower concentration lower than that in the first concentration.

Abstract: According to one embodiment, a nitride semiconductor element includes a functional layer and a stacked body. The stacked body includes a GaN intermediate layer, a low Al composition layer, a high Al composition layer, and a first Si-containing layer. The low Al composition layer includes a nitride semiconductor having a first Al composition ratio. The low Al composition layer is provided between the GaN intermediate layer and the functional layer. The high Al composition layer includes a nitride semiconductor having a second Al composition ratio. The high Al composition layer is provided between the GaN intermediate layer and the low Al composition layer. The second Al composition ratio is higher than the first Al composition ratio. The first Si-containing layer is provided between the GaN intermediate layer and the high Al composition layer.

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer. The p-type semiconductor layer includes a first p-side layer, a second p-side layer, and a third p-side layer. A concentration profile of Mg of a p-side region includes a first portion, a second portion, a third portion, a fourth portion, a fifth portion, a sixth portion and a seventh portion. The p-side region includes the light emitting layer, the second p-side layer, and the third p-side layer. A Mg concentration of the sixth portion is not less than 1×1020 cm?3 and not more than 3×1020 cm?3. The Al concentration is 1/100 of the maximum value at a second position. A Mg concentration at the second position is not less than 2×1018 cm?3.

Abstract: According to one embodiment, a semiconductor light emitting element includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type separated from the first semiconductor layer in a first direction, a light emitting layer provided between the first and second semiconductor layers, and a first intermediate unit provided between the first semiconductor layer and the light emitting layer. The light emitting layer includes a well layer including a nitride semiconductor including In. The first intermediate unit includes stacked bodies. The stacked bodies are arranged in the first direction. Each of the stacked bodies includes a first layer of Inx1Ga1-x1N, a second layer of Aly1Ga1-y1N provided between the first layer and the light emitting layer to contact the first layer, and a third layer of Aly2Ga1-y2N provided between the second layer and the light emitting layer to contact the second layer.

Abstract: According to one embodiment, a semiconductor light emitting device includes n-type and p-type semiconductor layers containing a nitride semiconductor and a light emitting layer. The emitting layer includes a barrier layer containing III group elements, and a well layer stacked with the barrier layer and containing III group elements. The barrier layer is divided into a first portion on an n-type semiconductor layer side and a second portion on a p-type semiconductor layer side, an In composition ratio in the III group elements of the second portion is lower than that of the first portion. The well layer is divided into a third portion on an n-type semiconductor layer side and a fourth portion on a p-type semiconductor layer side, an In composition ratio in the III group elements of the fourth portion is higher than that of the third portion.

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type layer, a p-type layer, and a light emitting unit provided between the n-type layer and the p-type layer and including barrier layers and well layers. At least one of the barrier layers includes first and second portion layers. The first portion layer is disposed on a side of the n-type layer. The second portion layer is disposed on a side of the p-type layer, and contains n-type impurity with a concentration higher than that in the first portion layer. At least one of the well layers includes third and fourth portion layers. The third portion layer is disposed on a side of the n-type layer. The fourth portion layer is disposed on a side of the p-type layer, and contains n-type impurity with a concentration higher than that in the third portion layer.

Abstract: According to one embodiment, a crystal growth method is disclosed for growing a crystal of a nitride semiconductor on a major surface of a substrate. The major surface is provided with asperities. The method can include depositing a buffer layer on the major surface at a rate of not more than 0.1 micrometers per hour. The buffer layer includes GaxAl1-xN (0.1?x<0.5) and has a thickness of not smaller than 20 nanometers and not larger than 50 nanometers. In addition, the method can include growing the crystal including a nitride semiconductor on the buffer layer at a temperature higher than a temperature of the substrate in the depositing the buffer layer.

Abstract: According to one embodiment, a semiconductor light emitting device includes: a foundation layer, a first semiconductor layer, a light emitting part, and a second semiconductor layer. The foundation layer includes a nitride semiconductor. The foundation layer has a dislocation density not more than 5×108 cm?2. The first semiconductor layer of a first conductivity type is provided on the foundation layer and includes a nitride semiconductor. The light emitting part is provided on the first semiconductor layer. The light emitting part includes: a plurality of barrier layers; and a well layer provided between the barrier layers. The well layer has a bandgap energy smaller than a bandgap energy of the barrier layers and has a thickness larger than a thickness of the barrier layers. The second semiconductor layer of a second conductivity type different from the first conductivity type, is provided on the light emitting part and includes a nitride semiconductor.

Abstract: According to one embodiment, a semiconductor light emitting element includes an n-type semiconductor layer including a nitride semiconductor, a p-type semiconductor layer and a light emitting layer. The p-type semiconductor layer includes a first p-side layer of Alx1Ga1?x1N (0?x1<1) including Mg, a second p-side layer of Alx2Ga1?x2N (0<x2<1) including Mg and a third p-side layer of Alx3Ga1?x3N (x2<x3<1) including Mg. The light emitting layer is provided between the n-type semiconductor layer and the second p-side layer. The light emitting layer includes barrier layers and well layers. Each of the well layers is provided between the barrier layers. A p-side barrier layer of the barrier layers most proximal to the second p-side layer includes a first layer of Alz1Ga1?z1N (0?z1), and a second layer of Alz2Ga1?z2N (z1<z2<x2).

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer. The p-type semiconductor layer includes a first p-side layer, a second p-side layer, and a third p-side layer. A concentration profile of Mg of a p-side region includes a first portion, a second portion, a third portion, a fourth portion, a fifth portion, a sixth portion and a seventh portion. The p-side region includes the light emitting layer, the second p-side layer, and the third p-side layer. A Mg concentration of the sixth portion is not less than 1×1020 cm?3 and not more than 3×1020 cm?3. The Al concentration is 1/100 of the maximum value at a second position. A Mg concentration at the second position is not less than 2×1018 cm?3.

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting part, and a p-side electrode. The light emitting part is provided between the n-type and the p-type semiconductor layers, and includes a plurality of barrier layers and a plurality of well layers. The p-side electrode contacts the p-type semiconductor layer. The p-type semiconductor layer includes first, second, third, and fourth p-type layers. The first p-type layer contacts the p-side electrode. The second p-type layer contacts the light emitting part. The third p-type layer is provided between the first p-type layer and the second p-type layer. The fourth p-type layer is provided between the second p-type layer and the third p-type layer. The second p-type layer contains Al and contains a p-type impurity in a lower concentration lower than that in the first concentration.

Abstract: According to one embodiment, a semiconductor light emitting device includes: a foundation layer, a first semiconductor layer, a light emitting part, and a second semiconductor layer. The foundation layer includes a nitride semiconductor. The foundation layer has a dislocation density not more than 5×108 cm?2. The first semiconductor layer of a first conductivity type is provided on the foundation layer and includes a nitride semiconductor. The light emitting part is provided on the first semiconductor layer. The light emitting part includes: a plurality of barrier layers; and a well layer provided between the barrier layers. The well layer has a bandgap energy smaller than a bandgap energy of the barrier layers and has a thickness larger than a thickness of the barrier layers. The second semiconductor layer of a second conductivity type different from the first conductivity type, is provided on the light emitting part and includes a nitride semiconductor.

Abstract: According to one embodiment, a method is disclosed for manufacturing a nitride semiconductor layer. The method can include forming a first nitride semiconductor layer on a substrate in a reactor supplied with a first carrier gas and a first source gas. The first nitride semiconductor layer includes indium. The first carrier gas includes hydrogen supplied into the reactor at a first flow rate and includes nitrogen supplied into the reactor at a second flow rate. The first source gas includes indium and nitrogen and supplied into the reactor at a third flow rate. The first flow rate is not less than 0.07% and not more than 0.15% of a sum of the first flow rate, the second flow rate, and the third flow rate.

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer. The p-type semiconductor layer includes a first p-side layer, a second p-side layer, and a third p-side layer. A concentration profile of Mg of a p-side region includes a first portion, a second portion, a third portion, a fourth portion, a fifth portion, a sixth portion and a seventh portion. The p-side region includes the light emitting layer, the second p-side layer, and the third p-side layer. A Mg concentration of the sixth portion is not less than 1×1020 cm?3 and not more than 3×1020 cm?3. The Al concentration is 1/100 of the maximum value at a second position. A Mg concentration at the second position is not less than 2×1018 cm?3.

Abstract: According to one embodiment, a semiconductor light emitting device includes n-type and p-type semiconductor layers containing a nitride semiconductor and a light emitting layer. The emitting layer includes a barrier layer containing III group elements, and a well layer stacked with the barrier layer and containing III group elements. The barrier layer is divided into a first portion on an n-type semiconductor layer side and a second portion on a p-type semiconductor layer side, an In composition ratio in the III group elements of the second portion is lower than that of the first portion. The well layer is divided into a third portion on an n-type semiconductor layer side and a fourth portion on a p-type semiconductor layer side, an In composition ratio in the III group elements of the fourth portion is higher than that of the third portion.

Abstract: According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting part, and a p-side electrode. The light emitting part is provided between the n-type and the p-type semiconductor layers, and includes a plurality of barrier layers and a plurality of well layers. The p-side electrode contacts the p-type semiconductor layer. The p-type semiconductor layer includes first, second, third, and fourth p-type layers. The first p-type layer contacts the p-side electrode. The second p-type layer contacts the light emitting part. The third p-type layer is provided between the first p-type layer and the second p-type layer. The fourth p-type layer is provided between the second p-type layer and the third p-type layer. The second p-type layer contains Al and contains a p-type impurity in a lower concentration lower than that in the first concentration.

Abstract: According to one embodiment, a nitride semiconductor element includes a functional layer and a stacked body. The stacked body includes a GaN intermediate layer, a low Al composition layer, a high Al composition layer, and a first Si-containing layer. The low Al composition layer includes a nitride semiconductor having a first Al composition ratio. The low Al composition layer is provided between the GaN intermediate layer and the functional layer. The high Al composition layer includes a nitride semiconductor having a second Al composition ratio. The high Al composition layer is provided between the GaN intermediate layer and the low Al composition layer. The second Al composition ratio is higher than the first Al composition ratio. The first Si-containing layer is provided between the GaN intermediate layer and the high Al composition layer.

Abstract: In general, according to one embodiment, a semiconductor light emitting element includes: a first semiconductor layer; a second semiconductor layer; a light emitting layer. The light emitting layer includes a well layer with a thickness of t1 (nanometers). The well layer includes InxGa1-xN having an In composition ratio x higher than 0 and lower than 1. The first semiconductor layer has a tensile strain of not less than 0.02 percent and not more than 0.25 percent in a plane perpendicular to a stacking direction. A peak wavelength ?p (nanometers) of light satisfies a relationship of ?p=a1+a2×(x+(t1?3.0)×a3). The a1 is not less than 359 and not more than 363. The a2 is not less than 534 and not more than 550. The a3 is not less than 0.0205 and not more than 0.0235.

Abstract: According to one embodiment, a semiconductor light emitting device includes n-type and p-type semiconductor layers containing a nitride semiconductor and a light emitting layer. The emitting layer includes a barrier layer containing III group elements, and a well layer stacked with the barrier layer and containing III group elements. The barrier layer is divided into a first portion on an n-type semiconductor layer side and a second portion on a p-type semiconductor layer side, an In composition ratio in the III group elements of the second portion is lower than that of the first portion. The well layer is divided into a third portion on an n-type semiconductor layer side and a fourth portion on a p-type semiconductor layer side, an In composition ratio in the III group elements of the fourth portion is higher than that of the third portion.