Semiconductor light-emitting device, exposure head, and image forming apparatus

A semiconductor light-emitting device comprising:

• a semiconductor stacked structure in which a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type opposite to the first conductivity type, a third semiconductor layer of the first conductivity type, and a fourth semiconductor layer of the second conductivity type are stacked in this order, the semiconductor stacked structure including a light-emitting layer;
• a metal electrode provided over the semiconductor stacked structure;
• and
• a transparent electrode provided over the semiconductor stacked structure and over the metal electrode,
• wherein the fourth semiconductor layer includes a first layer having a first impurity concentration and a second layer as a contact layer having a second impurity concentration higher than the first impurity concentration, and
• wherein the metal electrode is provided so as to surround a circumference of the second layer in a plan view.