Hitachi Cable, Inc.

Tooru Kurihara

Seiji Mizuniwa

Masahiro Noguchi

Toshiya Toyoshima

Seigi Aoyama

Akio Hattori

Konichi Nakamura

A Light-emitting diode having improved moisture resistance characteristics comprises a p-type gallium arsenide substrate and four epitaxial layers of Al.sub.x Ga.sub.1-x As (22, 23, 24 and 25). These epitaxial layers comprises an intervening layer (22) of p-type Al.sub.x1 Ga.sub.1-x1 As, a cladding layer (23) of p-type Al.sub.x2 Ga.sub.1-x2 As, an active layer (24) of Al.sub.x3 Ga.sub.1-x3 As, and a window layer (25) of Al.sub.x4 Ga.sub.1-x4 As so as to form a double-hetero structure, where x1, x2, x3 and x4 represent mixed crystal ratios of aluminum to arsenic of the layers, respectively, and meet the condition that:

Light-emitting diode having moisture-proof characteristics and high

A light-emitting diode having improved moisture resistance characteristics comprises a p-type gallium arsenide substrate and four epitaxial layers of Al.sub.x Ga.sub.1-x As (22, 23, 24 and 25). These epitaxial layers comprises an intervening layer (22) of p-type Al.sub.x Ga.sub.1-x As, a cladding layer (23) of p-type Al.sub.x2 Ga.sub.1-x2 As, an active layer (24) of Al.sub.x3 Ga.sub.1-x3 As, and a window layer (25) of Al.sub.x4 Ga.sub.1-x4 As so as to form a double-hetero structure, where x1, x2, x3 and x4 represent mixed crystal ratios of aluminum to arsenic of the layers, respectively, and meet the condition that:

Method for making light-emitting diode having improved moisture

A method of fabricating an undoped or impurity-doped semi-insulating GaAs single crystal with the use of a silica boat comprises the steps of making a melt of GaAs in the silica boat except for a seed crystal, doping the melt with oxygen, maintaining the doped melt as it is for a predetermined period of time, solidifying the melt from the side opposite the seed crystal toward the seed crystal, seeding the melt when the melt attains a predetermined melt zone width on the seed crystal side, and moving the melt zone in the direction opposite the seed crystal for its solidification while keeping the melt zone width unchanged.

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Ibaraki-ken, Japan

Tooru Kurihara