Abstract: A light-emitting element includes a first semiconductor layer doped to a first conductivity type, an active layer disposed on the first semiconductor layer, a second semiconductor layer disposed on the active layer, the second semiconductor layer doped to a second conductivity type, and a passivation layer surrounding surfaces of the active layer, the passivation layer including a side surface of the active layer, and the passivation layer includes a semiconductor material that matches a lattice of a semiconductor material contained in the active layer, the semiconductor material has a band gap energy higher than that of the semiconductor material contained in the active layer.

Abstract: A toy-type device which is adapted for both yo-yo play and ball-catching play utilizing a ball tethered to a disc-shaped body, wherein the ball can be used as a grasping element when the device is used as a yo-yo or alternatively the ball can be used as a free-body adapted to be caught by the disc-shaped body.

Abstract: Disclosed herein is a yo-yo which provides a player with a yo-yo play and a ball-catching play.