Optically Activated Transistor Using Germanium Selenide Layers
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Solution Overview
Problem
Conventional transistors require a third terminal and additional voltage for operation, limiting their use in applications where a gate signal is not in the form of voltage, and existing photodiodes do not exhibit transistor-like electrical characteristics.
Innovation Solution
An optically activated device with a substrate and active material, comprising multiple layers of germanium selenide (GeSe) and an element, which conducts current only in the presence of light, allowing it to function as a transistor, switch, and photodiode with two terminals, and is flexible for use on various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional transistor is used to control current flow, then current switching is achieved, but an additional voltage signal and third terminal are required
Solution Approach 1:
The patent extracts and removes the gate terminal from the transistor structure, reducing it from three terminals to two terminals. The optically activated material directly replaces the gate terminal's function by responding to light intensity changes, eliminating the need for a separate gate electrode and control voltage signal.
Solution Approach 2:
The patent substitutes the electrical control mechanism (voltage signal applied to gate terminal) with an optical control mechanism (light intensity modulation). The optically activated material's conductivity changes in response to light, replacing the traditional electrical field control of conventional transistors.
2Adaptability or versatility
If a photodiode is used to detect light, then light detection is achieved, but transistor-like electrical characteristics are not exhibited
Solution Approach 1:
The patent creates a single device that performs multiple functions: it detects light (photodiode function) and simultaneously provides current switching and amplification (transistor function). The optically activated material enables the device to respond to light intensity changes while maintaining transistor-like electrical characteristics including current gain and switching capability.
Solution Approach 2:
The patent merges the photodiode's light detection function with the transistor's current control function into a single integrated device. The optically activated material serves both as a light sensor and as a controlled conductor, combining previously separate functionalities into one unified component.
3Ease of manufacture
If additional hardware such as optical/electrical converters is used for interfacing, then circuit isolation is achieved, but device complexity increases
Solution Approach 1:
The patent creates a device that directly interfaces between optical and electrical domains without requiring external converters. The optically activated material inherently converts light signals to electrical signals while maintaining transistor functionality, eliminating the need for separate optical/electrical converter components.
Solution Approach 2:
The patent merges the optical-to-electrical conversion function with the transistor switching function into a single integrated device, rather than using separate converter and transistor components. This integration simplifies the overall system architecture and reduces the number of discrete hardware elements required.
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
Enables direct interfacing between electrical and optical circuits without additional hardware, with current conduction dependent on light intensity and wavelength, and exhibits current-voltage curves similar to conventional FETs, facilitating electrical isolation and bidirectional current flow.
Implementation Method 1
The active material conducts current in the presence of light, but only conducts a very small amount of current in the absence of light
Data Source
AI summary
An optically activated device that includes an active material on a substrate with two electrodes electrically connected to the active material, the active material conducts current in the presence of light and does not conduct appreciable current in the absence of light. The optically activated device functions as a photodiode, a switch, and an optically gated transistor. The optically activated device conducts current in the presences of light. The active material may be layers of germanium selenide and germanium selenide and an element. Germanium selenide may be sputtered onto a substrate to create layers of material separated by layers of co-sputtered germanium selenide with the element. The active material may be deposited onto a flexible substrate.