Extended Infrared Photoresponse inTe-HyperdopedSiat Room Temperature

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-bandgap 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. Temperaturedependent optoelectronic photoresponse unambiguously demonstrates that the extended infrared photoresponsivity from Te-hyperdoped Si p-n photodiodes is mediated by a Teintermediate band within the upper half of the Si bandgap. This work contributes to pave the way towards establishing a Si-based broadband infrared photonic system operating at room temperature.

Copper Iron Sulfide Nanocrystal‐Bulk Silicon Heterojunctions for Broadband Photodetection

“…The observed response could independently arise either from defects inherent in heavily doped silicon or else from defects present in CuFeS 2 nanocrystals. [ 11,34,35 ] In particular, the creation of extra carriers through the photoexcitation of defects can also compensate and effectively neutralize the noncompensated charged dopants (e.g., phosphorus donors in n‐Si) in the depletion region. The effective compensation of the charged donors can lead to an increase in the mobility of the charge carriers and hence enhance the PC and lead to a nonlinear dependence of PC on power as is observed in our experiments.…”

Simudo: a device model for intermediate band materials

“…A new class of materials, called intermediate band (IB) materials, has been developed over the last 20 years with the goal of improving solar cell efficiency and producing effective infrared photodetectors [6][7][8][9][10]. These IB materials are like semiconductors except they have an extra band of allowed electronic energy levels above the valence band (VB) and below the conduction band (CB), as shown in Fig.…”

“…Where IB devices have been made, they have not generally been highly efficient, which is believed to be largely due to fast nonradiative recombination processes [7][8][9][10][12][13][14][15]]. It has not been possible, however, to perform standard device modeling to optimize these devices, to determine the ideal layer thicknesses, doping levels, etc., since standard semiconductor device models do not allow the possibility of treating a third band.…”

Infinitesimal sulfur fusion yields quasi-metallic bulk silicon for stable and fast energy storage

“…Such doping is enabled by a safe, scalable, and feasible approach, in contrast with conventional high-risk and toxic methods. In addition to sulfur dopants, other chalcogens including selenium or tellurium are expected to induce insulator-to-metal transition in the same way but with different critical doping concentrations as reported previously 45,46 . Whether these larger atoms form the chain-like structure that creates diffusion channels for metal ions raises an open question; otherwise, the air-stable binary phase will appear rather than simultaneously featuring metallicity and channel formation 47 .…”