The Impact of Implanting Cr+ Ion onto ALD PbTe Thin Films
College
College of Engineering & Technology (Batten)
Department
Department of Electrical and Computer Engineering
Graduate Level
Doctoral
Graduate Program/Concentration
Electrical Engineering
Presentation Type
Poster Presentation
Abstract
Inherently the synthesis of semiconducting materials by Atomic Layer Deposition (ALD) produces only intrinsic undoped films which require the introduction of small amounts of impurities for doping to change them into extrinsic semiconductors. Apart from various in-situ diffusion doping techniques like delta doping during the ALD process, post deposition doping by ion implantation affords the best control of dose and doping profile. The present study investigates the impact of Cr+ ion implantation onto Lead Telluride (PbTe) thin films to improve their thermoelectric figure of merit. The implantation was accomplished with 180 keV Chromium ions at a given fluence to reach a desired 1% Cr doping level. These thermoelectric PbTe thin films have been synthesized on silicon substrates covered with native oxide by ALD with the growth temperature during ALD range from 130 centidegree to 170 centidegree. Several physical characterization techniques among them SEM and EDS have been employed to determine the ALD PbTe thin film characteristics before and after Chromium in implantation. X- ray diffraction analysis reveals that the films exhibit a polycrystalline structure with simple cubic crystallites. Atomic force microscopy analysis was employed to determine the surface properties of the films, including surface topology, root mean square (RMS) roughness, grain height, and average size. For the electrical characterization we report the effects of the ion implantation on the resistivity ρ(T) as a function of temperature, the electrical conductivity, the Hall mobility, and the Seebeck coefficient.
Keywords
ALD, PbTe, Thermoelectrics, Implant, Nanostructure, Chromium, Cr+
The Impact of Implanting Cr+ Ion onto ALD PbTe Thin Films
Inherently the synthesis of semiconducting materials by Atomic Layer Deposition (ALD) produces only intrinsic undoped films which require the introduction of small amounts of impurities for doping to change them into extrinsic semiconductors. Apart from various in-situ diffusion doping techniques like delta doping during the ALD process, post deposition doping by ion implantation affords the best control of dose and doping profile. The present study investigates the impact of Cr+ ion implantation onto Lead Telluride (PbTe) thin films to improve their thermoelectric figure of merit. The implantation was accomplished with 180 keV Chromium ions at a given fluence to reach a desired 1% Cr doping level. These thermoelectric PbTe thin films have been synthesized on silicon substrates covered with native oxide by ALD with the growth temperature during ALD range from 130 centidegree to 170 centidegree. Several physical characterization techniques among them SEM and EDS have been employed to determine the ALD PbTe thin film characteristics before and after Chromium in implantation. X- ray diffraction analysis reveals that the films exhibit a polycrystalline structure with simple cubic crystallites. Atomic force microscopy analysis was employed to determine the surface properties of the films, including surface topology, root mean square (RMS) roughness, grain height, and average size. For the electrical characterization we report the effects of the ion implantation on the resistivity ρ(T) as a function of temperature, the electrical conductivity, the Hall mobility, and the Seebeck coefficient.