Light emitting device with graded composition hole tunneling layer

Abstract

A light emitting device with graded composition hole tunneling layer is provided. The device comprises a substrate and an n-type semiconductor layer is disposed on the substrate, in which the n-type semiconductor layer comprises a first portion and a second portion. A graded composition hole tunneling layer is disposed on the first portion of the n-type semiconductor layer. An electron blocking layer is disposed on the graded composition hole tunneling layer. A p-type semiconductor layer is disposed on the electron blocking layer. A first electrode is disposed on the p-type semiconductor layer, and a second electrode is disposed on the second portion of the n-type semiconductor layer and is electrical insulated from the first portion of the n-type semiconductor. The graded composition hole tunneling layer is used as the quantum-well to improve the transport efficiency of the holes to increase the light emitting efficiency of the light emitting device.