author = "Pirralho, Mar{\'{\i}}lia de J. P. and Peres, Marcelo L. and 
                         Soares, Dem{\'e}trio A. W. and Okasaki, Anderson K. and Fornari, 
                         Celso Israel and Rappl, Paulo Henrique de Oliveira and Abramof, 
          affiliation = "{} and {} and {} and {} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Transition from negative to positive photoconductivity in p-type 
                         Pb1-xEuxTe films",
            booktitle = "Resumos...",
                 year = "2017",
         organization = "Brazilian Workshop on Semiconductor Physics, 18. (BWSP)",
             abstract = "The phenomenon of photoconductivity has been used as an important 
                         tool to investigate the presence of additional states within the 
                         band structure of semiconductors [1] and has provided basic 
                         knowledge that allowed the development of photodetector and sensor 
                         devices along the last decades [2]. We investigated the 
                         photoconductivity effect in p-type Pb1-xEuxTe films for x=0.01, 
                         0.02, 0.03, 0.05 and 0.06 at T=300K. The measurements revealed a 
                         clear transition from negative to positive photoconductivity as 
                         the Eu content x is increased at room temperature. This transition 
                         is related to the metal-insulator transition that occurs due to 
                         the disorder originated from the introduction of Eu atoms and it 
                         is an Anderson transition. Our investigation found that, from the 
                         potential application point of view, the sample x=0.06 is more 
                         suitable, i.e. it presents an almost noise free signal and the 
                         higher photoconductivity amplitude response observed. The 
                         photoconductive for the sample with x=0.06 was further 
                         investigated in the temperature range of 77 300K and, 
                         surprisingly, multiple additional transitions were observed with 
                         amplitudes that reached around 200 times the original value before 
                         illumination. We show that this anomalous behavior is a 
                         consequence of the generation and recombination rates between the 
                         bands and the 4f level and a defect level located inside the 
                         bandgap. The main goal of this work is to make a prospective study 
                         of NPC effect in p-type Pb1-xEuxTe films in both sides of the 
                         metal-insulator transition aiming to possible new applications in 
                         the development of photonic devices that operate from low 
                         temperature up to room temperature. Acknowledgments: The authors 
                         would like to acknowledge CAPES and FAPEMIG for support. 
                         References: [1] M. M. Furchi et al, Nano Letters 14, 6165-6170 
                         (2014); [2] R. Jaramillo et al, Jour. Appl. Phys. 119, 035101 
  conference-location = "Maresias, SP",
      conference-year = "14-18 ago.",
             language = "en",
        urlaccessdate = "01 dez. 2020"