P-type Molybdenum Oxide Heterojunction for Reduced Carrier Recombination

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Solution Overview

Problem

Current semiconductor devices face challenges in achieving high output voltage and conversion efficiency due to difficulties in forming a favorable p-n heterojunction interface and suppressing carrier recombination, particularly when using wide-gap semiconductor materials with p-type conductivity, which leads to reduced photocurrent and output current.

Innovation Solution

A semiconductor device is developed using a p-type oxide semiconductor material, specifically molybdenum trioxide (MoO3) with an intermediate composition of molybdenum oxide (MoOy) (2<y<3), which is integrated with a silicon substrate to form a p-n heterojunction, reducing light absorption loss and enhancing carrier extraction and interface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a wide-gap semiconductor material with p-type conductivity is used to form a p-n heterojunction, then output voltage and conversion efficiency are improved, but carrier recombination increases and photocurrent is reduced

Engineering Contradiction:

Improveoutput voltageVSAvoidcarrier recombination

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent changes the chemical composition parameter of the oxide semiconductor from stoichiometric MoO3 to non-stoichiometric MoOy (2<y<3), which modifies the material's electrical and optical properties to reduce carrier recombination while maintaining high output voltage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite heterojunction structure combining silicon substrate with oxide semiconductor material (MoOy), where the two materials with different band gaps work together to achieve both high output voltage and reduced carrier recombination

Inventive Principle:

Principle #40Composite materials

2Power

If a wide-gap semiconductor material with p-type conductivity is used to form a p-n heterojunction, then conversion efficiency is improved, but light absorption loss increases

Engineering Contradiction:

Improveconversion efficiencyVSAvoidlight absorption loss

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent modifies the optical properties by changing the composition from MoO3 to MoOy (2<y<3), which adjusts the band gap and light absorption characteristics to reduce energy loss while maintaining high conversion efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent optimizes the local optical properties of the window layer by using non-stoichiometric oxide semiconductor, creating a material that is transparent to useful light wavelengths while maintaining the necessary electrical properties for high conversion efficiency

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If a p-n heterojunction is formed with wide-gap semiconductor material, then interface quality is improved, but manufacturing difficulty increases

Engineering Contradiction:

Improveinterface qualityVSAvoidmanufacturing difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent uses a composite material system of silicon and oxide semiconductor that forms a heterojunction with naturally high interface quality, where the material combination itself facilitates good interface formation without requiring excessively complex manufacturing processes

Inventive Principle:

Principle #40Composite materials

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 enables improved open-circuit voltage and conversion efficiency by minimizing carrier recombination and light absorption loss, thereby enhancing the performance of semiconductor devices such as photoelectric conversion devices.

Implementation Method 1

a semiconductor device including a silicon substrate having n-type conductivity; an oxide semiconductor layer having p-type conductivity over one surface of the silicon substrate

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

an oxide semiconductor layer having p-type conductivity over one surface of the silicon substrate

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9159793B2P-type semiconductor material and semiconductor device

Publication Date: 2015.10.13 SEMICON ENERGY LAB CO LTD

AI summary

An oxide semiconductor material having p-type conductivity and a semiconductor device using the oxide semiconductor material are provided. The oxide semiconductor material having p-type conductivity can be provided using a molybdenum oxide material containing molybdenum oxide (MoOy (2<y<3)) having an intermediate composition between molybdenum dioxide and molybdenum trioxide. For example, a semiconductor device is formed using a molybdenum oxide material containing molybdenum trioxide (MoO3) as its main component and MoOy (2<y<3) at 4% or more.