Nano-Column Light Emitting Structure for Current Leakage Suppression

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Solution Overview

Problem

Semiconductor photonic element arrays with nano-columns are prone to crystal faults on their side surfaces, leading to electrical current leakage between the n-type and p-type semiconductor layers, which affects light emission efficiency.

Innovation Solution

A light emitting device with a laminated structure comprising columnar parts, where the second semiconductor layer has a lower impurity concentration than the first semiconductor layer and is arranged to surround the light emitting layer, reducing electrical current leakage and enhancing light emission efficiency by minimizing crystal faults.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a nano-column structure is used to achieve high power and narrow radiation angle, then light emission efficiency is improved, but crystal faults occur on the side surface causing electrical current leakage

Engineering Contradiction:

Improvelight emission powerVSAvoidelectrical current leakage

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies local quality by creating a graded impurity concentration distribution within the second semiconductor layer. The impurity concentration is lower at the peripheral portion (near side surface) and higher at the central portion, allowing different regions to serve different functions: the peripheral region suppresses current leakage while the central region maintains conductivity for light emission

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the impurity concentration parameter spatially within the second semiconductor layer. By varying the impurity concentration from the peripheral portion to the central portion, the patent optimizes both the suppression of electrical current leakage at the boundaries and the maintenance of electrical conductivity in the emission region

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the second semiconductor layer has high impurity concentration to ensure conductivity, then electrical conduction is improved, but crystal faults increase on the side surface

Engineering Contradiction:

Improveelectrical conductionVSAvoidcrystal faults

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the potentially harmful high impurity concentration that causes crystal faults into a beneficial graded distribution. By strategically placing lower impurity concentration at the peripheral portion where crystal faults occur, the patent transforms the uniform high concentration problem into a spatially optimized structure that suppresses faults while maintaining overall conductivity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces electrical current leakage between semiconductor layers, allowing for efficient injection of current into the light emitting layer and improved light emission, thereby enhancing the efficiency and quality of the light emitting device.

Implementation Method 1

the third semiconductor layer includes a light emitting layer... efficient injection of current into the light emitting layer and improved light emission

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

the semiconductor laser having a nano-structure called a nano-column, a nano-wire, a nano-rod, a nano-pillar, or the like is expected to realize a light emitting device capable of obtaining light emission narrow in radiation angle and high in power due to an effect of a photonic crystal

Methodology Applied

Scientific EffectPhotonic crystal effect: Photonic Crystal

Data Source

PatentUS12199402B2Light emitting device and projector

Publication Date: 2025.01.14 SEIKO EPSON CORP

AI summary

A light emitting device includes a laminated structure having a plurality of columnar parts, wherein the columnar part includes a first semiconductor layer, a second semiconductor layer different in conductivity type from the first semiconductor layer, and a third semiconductor layer disposed between the first semiconductor layer and the second semiconductor layer, the third semiconductor layer includes a light emitting layer, and the second semiconductor layer includes a first portion, and a second portion which surrounds the first portion in a plan view from a laminating direction of the first semiconductor layer and the light emitting layer, and is lower in impurity concentration than the first portion.