The Development of Compound Based Light-Addressable Ion Sensor with Back Side Light Source Array

In the development of a light addressable potentiometric sensor (LAPS), there is an evolution from the average data received via single light source, to the use of laser scanning in order to detect more information and also, higher pixels is achieved. However, more time is consumed and larger space is occupied due to the big facility volume in the scanning measurement process. In this project, we propose the use of our MOCVD system and double side epitaxial growth technique, in order to create a compound semiconductor based LAPS platform. On the backside LED array is made, the front side is based of an electrolyte insulator semiconductor (EIS) structure and so as to integrate both together. The sensor is equipped with a frequency modulator for the LED array driving circuit, which is able to quickly scan the pixel in a short period of time. Such design brings about an innovative idea regards LAPS. In the first year, we will grow GaN LED array on Sapphire substrate and GaN EIS on Sapphire separately. And then, by using the wafer bonding technology, EIS and LED array are bonded backside to backside together. We can also design the driving circuit to drive a 5x5 prototype LED array in the same period. In the second year, we will focus our study on the double-sided GaN epitaxial growth on the Sapphire or SiC substrates, so that EIS structure and optical light source may be fully integrated into a LAPS structure. In the second year progression, our team will also try to solve the surface contamination problem during the regrowth of LED epitaxial fabrication. Next step onwards; we can grow EIS together with LED array and improve the LED light divergence problem, which can result in a low-resolution phenomenon. In the third year, our team will attempt a double-sided epitaxial growth on the heterogeneous (GaN/Sapphire/GaN, GaN/SiC) substrate. The LAPS device will consist of an EIS structure on the front side and a 2D-LED structure on the back for application and measurement. Additionally, by incorporating data from the past two years, LAPS device will undergo 2-D scanning, including signal optimization and sensing membrane selection. This will also complete the integration of light source and sensor together, in the formation of a small volume high-speed one-bodied light addressable potentiometric sensor.

Project ID:PB10308-2690
External Project ID:MOST103-2221-E182-025