Polycrystalline PbTe:In Films on Amorphous Substrate: Structure and Physical Properties

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Research

Background:

• Polycrystalline lead telluride (PbTe) films are promising for infrared optoelectronics.
• Indium (In) doping in PbTe is known to stabilize the Fermi level, enabling controlled carrier concentrations.
• Developing uncooled photodetectors requires materials with high carrier mobility and long electron mean free paths.

Purpose of the Study:

• To investigate the structural and transport properties of polycrystalline PbTe:In films on polyimide substrates.
• To understand the effect of heat treatment on the properties of these films.
• To extract grain boundary scattering contributions to mobility for optimizing film design.

Main Methods:

• Fabrication of polycrystalline PbTe:In films on polyimide substrates.
• Structural and transport property measurements over a temperature range of 10-300 K.
• Heat treatment in an argon atmosphere.
• Analysis of Hall mobility, carrier concentration, and electron mean free path.

Main Results:

• Heat treatment in argon did not alter grain size or carrier concentration.
• Argon heat treatment significantly increased Hall mobility and electron mean free path.
• Grain boundary scattering mobility was successfully extracted by comparing bulk and film properties.
• Fermi level stabilization by In impurity allowed for consistent carrier concentration.

Conclusions:

• Heat treatment is an effective method to enhance the transport properties of polycrystalline PbTe:In films.
• Understanding grain boundary scattering is key to further improving film performance.
• These enhanced PbTe:In films show significant potential for portable uncooled mid-IR photodetectors.