Extended Infrared Photoresponse in Te-Hyperdoped Si at Room Temperature

TL;DR

This paper demonstrates room-temperature infrared photodetectors using tellurium-hyperdoped silicon, which exhibits enhanced mid-infrared response due to an intermediate band, advancing silicon-based broadband infrared photonics.

Contribution

The study introduces a novel Te-hyperdoped silicon fabrication method that achieves strong room-temperature infrared photoresponse through an intermediate band mechanism.

Findings

Te-hyperdoped Si layers show increased optical absorptance into mid-infrared.

Photoresponse is mediated by a Te intermediate band within the Si band gap.

The hyperdoped layers transition from insulating to quasi-metallic with higher Te concentrations.

Abstract

Presently, silicon photonics requires photodetectors that are sensitive in a broad infrared range, can operate at room temperature, and are suitable for integration with the existing Si-technology process. Here, we demonstrate strong room-temperature sub-band-gap photoresponse of photodiodes based on Si hyperdoped with tellurium. The epitaxially recrystallized Te-hyperdoped Si layers are developed by ion implantation combined with pulsed-laser melting and incorporate Te-dopant concentrations several orders of magnitude above the solid solubility limit. With increasing Te concentration, the Te-hyperdoped layer changes from insulating to quasi-metallic behavior with a finite conductivity as the temperature tends to zero. The optical absorptance is found to increase monotonically with increasing Te concentration and extends well into the mid-infrared range. Temperature-dependent optoelectronic photoresponse unambiguously demonstrates that the extended infrared photoresponsivity from Te-hyperdoped Si p-n photodiodes is mediated by a Te intermediate band within the upper half of the Si band gap. This work contributes to pave the way toward establishing a Si-based broadband infrared photonic system operating at room temperature.