研究目的
Study of influence of disorder in negative photoconductivity (NPC) in metallic p-type Pb1-xEuxTe epitaxial films and provide a general picture of the influence of disorder in photoconductivity properties of these materials.
研究成果
The study showed that disorder significantly affects the generation/recombination rates in p-type Pb1-xEuxTe films, leading to negative photoconductivity or transitions from positive to negative photoconductivity depending on the Eu content. The results provide insights into the role of defect levels in photoconductivity phenomena in these materials.
研究不足
Hall measurements were not suitable for a conclusive analysis of the anomalies observed in photoconductivity. The study is limited to p-type Pb1-xEuxTe films with x~0.02 and x~0.03.
1：Experimental Design and Method Selection:
Photoconductivity measurements were performed on p-type Pb1-xEuxTe epitaxial films under IR illumination. Hall measurements were also conducted to investigate transport parameters.
2：Sample Selection and Data Sources:
p-type Pb1-xEuxTe epitaxial films with x~0.02 and x~0.03 were grown using a molecular-beam epitaxy (MBE) system on BaF2 (111) substrates.
3：02 and x~03 were grown using a molecular-beam epitaxy (MBE) system on BaF2 (111) substrates.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: A 9-T He-cooled superconducting magnet, an infrared LED with a wavelength of 940nm and 12mW/m2, and a PID Lakeshore 303 temperature controller were used.
4：Experimental Procedures and Operational Workflow:
Films were grown at a substrate temperature of 208.50C during 2h, with a deposition rate of 3.9 ?/s. Photoconductivity and Hall measurements were performed in the temperature range of 77K – 300K.
5：50C during 2h, with a deposition rate of 9 ?/s. Photoconductivity and Hall measurements were performed in the temperature range of 77K – 300K.
Data Analysis Methods:
5. Data Analysis Methods: Recombination times were extracted from decay curves using exponential fitting. Activation energies were calculated from the temperature dependence of recombination times.
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