An alternative route to form a wide band-gap Cu(In,Al)S2 (CIAS) thin film with Al content of approximately 23 at.% and its application to ultraviolet (UV) photodetectors (PDs) have been demonstrated. X-ray diffraction patterns and scanning electron microscope micrographs show that the CIAS thin film, formed by 700°C sulfurization of Cu9Al4 (330) compound, is a single phased polycrystalline film with the (112)-preferred orientation and grain size of approximately 400-500 nm. At a 3 V bias voltage, the metal-semiconductor-metal structured UV PD has a dark current of 4.31 × 10-9 A and a photocurrent of 6.55 × 10-8 A using electrodes with 5-μm finger spacing. More than one order of magnitude in photocurrent amplification has been demonstrated. The spectral response of the PD is 0.72 A/W and the cut off wavelength occurs at 380 nm, which suggests that the band-gap of the CIAS film is 3.27 eV. The wide band-gap CIAS film has the potential to be a good candidate for UV PD applications.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry