The market for high quality UV photodiodes is dominated by detectors based on Silicon Carbide (SiC). All sglux Sensor probes work with SiC detectors.

However,  some applicants are advised to also have a look at alternative photodiodes concepts such as AlGaN and TiO2. sglux does research on TiO2 as basic material for UV photodiodes since 2001. In the Berlin cleanroom of the company these chips are produced and are subject of current further develoment. An actual development goal is the production of a flame sensing UV detector according to the standard EN298. For flame detection TiO2 can take advantage from the unique opportinity to produce very large active areas needed to detect low UV signal levels e.g. emitted by a burner flame. 

The picture shows an UV-photodiode on a Sol-Gel coated 10x10cm² wafer.

A variety of semiconductor materials can be found in the II-VI compounds with metal oxides and sulfides amongst.
Sol-Gel chemistry is an exceptionally attractive method for their synthesis. Its flexibility allows a tailoring of the optical and electronic semiconductor properties as it is necessary for trend setting optoelectronics.

sglux invented the process technology for a stable production of electronic components based on Sol-Gel chemistry. The substrate is coated with the thin film semiconductor by simply dipping it into solutions of liquid precursors. The benefits of such a cost-effective production are most competitive in the field of wide-bandgap optical detectors.
There, the established material SiC suffers from high material and plant costs which is particularly painful for photodetectors with a large sensing area and for consumer applications.

The REM-picture shows the semiconductur layers. We published details of the nature of the charge transport in our semiconductor layers in 2005.

sglux Schottky-type TiO₂ UV-photodiodes are inherently visible blind, being sensitive to ultraviolet radiation below = 400 nm only and not to visible light.
Due to the polycrystalline nature of our thin-film semiconductor the production effort scales only weakly with the chip's size. We therefore try to fit the largest possible photoactive area into the TO housings, giving many benefits like a large photocurrent and only a weak dependency on the incident angle.
The polycrystalline nature is also responsible for the superior UV-radiation hardness. The disadvantages compared to monocrystalline devices should not remain unmentioned: The response time is as long as 100 µs and the quantum efficiency does not exceed 20%.

However, the low sensitivity is easily over-compensated by the large photoactive area.

Please find here a list of currently offered TiO2 based UV photodiodes.