Visible to Short-Wave Infrared Photodetectors Based on ZrGeTe₄ van der Waals Materials

The self-terminated, layered structure of van der Waals materials introduces fundamental advantages for infrared (IR) optoelectronic devices. These are mainly associated with the potential for low noise while maintaining high internal quantum efficiency when reducing IR absorber thicknesses. In this study, we introduce a new van der Waals material candidate, zirconium germanium telluride (ZrGeTe₄), to a growing family of promising IR van der Waals materials. We find the bulk form ZrGeTe₄ has an indirect band edge around ∼0.5 eV, in close agreement with previous theoretical predictions. This material is found to be stable up to 140 °C and shows minimal compositional variation even after >30 days storage in humid air. We demonstrate simple proof-of-concept broad spectrum photodetectors with responsivities above 0.1 AW^-1 across both the visible and short-wave infrared wavelengths. This corresponds to a specific detectivity of ∼10⁹ cm Hz^1/2 W^-1 at λ = 1.4 μm at room temperature. These devices show a linear photoresponse vs illumination intensity relationship over ∼4 orders of magnitude, and fast rise/fall times of ∼50 ns, also verified by a 3 dB roll-off frequency of 5.9 MHz. As the first demonstration of photodetection using ZrGeTe₄, these characteristics measured on a simple proof-of-concept device show the exciting potential of the ZrGeTe₄ for room temperature IR optoelectronic applications.