Amorphous Se-Te Photodetector Biasing for Low-Mobility Alloys

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Solution Overview

Problem

Existing amorphous selenium (a-Se) alloys with tellurium (Te) suffer from reduced carrier mobility and increased defect states, limiting their practical utility in detector applications, particularly at low electric fields.

Innovation Solution

A detector design utilizing an amorphous selenium-tellurium alloy with an applied electric field of at least 20 V/μm, which mitigates mobility reduction and enhances quantum efficiency by operating at higher fields, optimizing sensitivity across a wide range of electromagnetic wavelengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If tellurium is added to amorphous selenium to improve optical absorbance and extend wavelength range, then absorption efficiency is improved, but carrier mobility is sharply reduced due to defect state formation

Engineering Contradiction:

Improveoptical absorbanceVSAvoidcarrier mobility

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent applies parameter changes by operating the Se-Te alloy detector at high electric fields (≥20 V/μm) rather than low fields, fundamentally changing the operating condition to overcome the mobility reduction effect. This allows the detector to achieve quantum efficiency comparable to pure a-Se despite the presence of Te-induced defect states.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by creating an amorphous alloy comprising selenium and tellurium, combining the high absorption properties of Te with the good charge transport properties of Se, achieving a balance between optical absorbance and carrier mobility through material composition.

Inventive Principle:

Principle #40Composite materials

2Reliability

If electric field is increased to at least 20 V/μm to overcome mobility reduction, then quantum efficiency is improved, but power consumption increases

Engineering Contradiction:

Improvequantum efficiencyVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameter (electric field strength) to ≥20 V/μm, which is significantly higher than conventional operating fields. This parameter change enables the detector to overcome the mobility reduction effect and achieve high quantum efficiency, though it does increase power consumption requirements.

Inventive Principle:

Principle #35Parameter changes

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 detector achieves quantum efficiency comparable to pure a-Se at low fields and surpasses it at higher fields, particularly in ultraviolet and blue wavelengths, expanding its application in X-ray imaging and other radiation detection systems.

Implementation Method 1

amorphous selenium (a-Se), with a bandgap of approximately ̃2 eV, is one of the best photoconductors used in the photocopy industry

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Implementation Method 2

the biasing circuit for applying an electric field of at least 20 Volts per micrometer between the first contact and the second contact and across the active region

Methodology Applied

Scientific EffectElectrical drift: Electrophoresis

Data Source

PatentUS20260047218A1Photodetector comprising amorphous selenium and optionally tellurium

Publication Date: 2026.02.12 RGT UNIV OF CALIFORNIA

AI summary

A photodetector comprising an amorphous alloy of selenium and tellurium. Also disclosed is a dual layer detector including the photodetector.