Polarization electric field assisted hole supplier and p-type contact structure, light emitting device and photodetector using the same

Abstract

A hole supplier and p-contact structure for a light emitting device or a photodetector includes a p-type group III nitride structure and a hole supplier and p-contact layer made of Al-containing group III nitride formed on the p-typegroup III nitride structure and being under a biaxial in-plane tensile strain, the hole supplier and p-contact layer has a thickness in the range of 0.6-10 nm, and the p-type group III nitride structure is formed over an active region of the light emitting device or photodetector. A light emitting device and a photodetector with a hole supplier and p-contact structure.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority of U. S.provisional application No.62 / 574,083, filed on Oct.18, 2017, entitled “POLARIZATION ELECTRIC FIELD ASSISTED TRANSPARENT HOLE SUPPLIER AND P-TYPE CONTACT STRUCTURE AND LIGHT EMITTING DEVICE USING THE SAME”, which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates in general to semiconductor light emitting technology and, more particularly, to a polarization electric field assisted hole supplier and p-type contact structure for a light emitting device or a photodetector, and to light emitting devices and photodetectors with a polarization electric field assisted holesupplier and p-type contact structure.DESCRIPTION OF THE RELATED ART[0003]Nitridecompound semiconductors such as InN, GaN, AlN, and their ternary and quaternary alloys depending on alloy compositionenable ultraviolet (UV) emissions ranging from 410 nm approximately to 200 nm. Thes...

AI Technical Summary

Benefits of technology

The present invention provides a hole supplier and p-type contact structure for UV light emitting devices and photodetectors. The structure has improved current-voltage characteristics and light extraction efficiency, leading to better performance of the device.

Problems solved by technology

However, the strong UV absorption (coefficient ˜105 cm−1)of p-type GaN and InGaN layers severely limits UV LEDs' light extraction efficiency (LEE) to be as small as 3%-6%.

The valence band and polarization discontinuities between AlGaN and GaN will lead to hole accumulation within the GaN wells.

However, the AlGaN / GaN valence band and polarization discontinuities will impede hole movement in the directions perpendicular to the GaN well plane.

This is to say, that p-type AlGaN / GaN superlattice can have improved lateral conductivity yet with limited vertical conductivity, not suitable for vertical hole injection into the MQW active-region for light emissions.

Images