Patent
Method of Fabricating an Ultra-Violet (UV) Photo Detector and System Thereof
Abstract
This invention details a method and system for fabricating an Ultra-Violet (UV) photo detector using a process called Chemical Vapor Deposition (CVD). It involves growing a Zinc Oxide (ZnO) layer on a Gallium Nitride (p-GaN) substrate. The junction formed between these two materials acts as an effective UV photodetector, offering improved performance over traditional methods.
Type of IP
Faculty
Category of Patent
Department
Societal Impact
- This UV photodetector is sustainable, self powered and maintenance free.
- It can detect faint signals quickly, making it useful for military applications like missile detection at high speeds.
- It can be used for space exploration to detect signals coming from celestial bodies.
- It also has multiple biomedical applications for diagnostics and treatment.
- Air/water purification, flame sensing, forest fire detection, submarine leakage monitoring are some other applications.
Salient technical features and Advantages of the Technology
- Improved Structural Quality: The use of a Chemical Vapor Deposition (CVD) process for growing epitaxial ZnO layers on a p-GaN template results in high-quality crystalline films with minimal dislocations.
- Responsivity and Low Leakage Current: The UV photodetector demonstrates a responsivity of 0.4 mA/W to UV light, particularly at 366 nm, with a significant enhancement in photocurrent. Additionally, the device shows very low leakage currents under dark conditions, indicating efficient photodetection with minimal background noise.
- Rapid Response Time: The invention boasts quick response times, with rise and decay times of 2.5 milliseconds and 3.5 milliseconds respectively, unlike conventional UV photodetectors which can range from 5 to 20 milliseconds.
- Enhanced On-Off Ratio: The on-off ratio of the photocurrent to dark current is significantly high, reaching a maximum of 1.6 x 104 at a forward bias of 0.25V, compared to existing technologies with a range of 102 to 103.
Technology readiness level
5
Current Status of Technology
- An early prototype has been developed, and testing has been done. The current size of the detector is around 6 mm, and it has a response time in the millisecond range. Further reducing the size would help get even better response times.
- Apart from CVD, the PLD technique has also been used to fabricate UV photodetectors, and it has shown even better responsivity of 11 mA/W and response time of 1 ms in self powered mode.
Relevant Industries
Medical, Military, Space, Agriculture, Marine
Applications or Domain
UV photodetectors have many applications in various areas such as engine control, solar UV monitoring, astronomy, lithography aligners, secure space-to-space communications, or detection of missiles. It also has applications in environmental monitoring and optoelectronics.