Evidences of sensitization mechanism for PbSe thin films photoconductor

Photoconductive PbSe thin films for infrared imaging

“…The PbSe thin films have unique intrinsic physical properties and band structure, widely used for the NIR and MWIR range applications. The PbSe polycrystalline thin films are widely used for IR detectors, [5][6][7][8][9] IR Photoluminescence, 10 diode laser, 11 up-conversion imaging devices, 12 imaging sensor devices, [13][14][15][16] thermoelectric coolers, 17 and IR solar cells. 3 Recently, the PbSe QD thin films are also being used for IR photodetectors, [18][19][20][21] photovoltaic cells, [22][23][24][25][26][27][28] IR electroluminescent, 29 thermoelectric, 30,31 laser, 32 and field-effect transistor (FET).…”

“…6 It is required to prevent the thermal generation of charge carriers; otherwise, it will increase the noise in the device performance. 5,36 The uncooled polycrystalline PbSe is an excellent choice for this regime. It can outperform other materials such as single crystalline indium antimonide (InSb) and mercury cadmium telluride (HgCdTe, also known as MCT).…”

“…6 The lead salt narrow bandgap IV-VI semiconductor alloys have provided an exceptional degree of freedom in IR detector design because of their energy bandgap tunability, high optical absorption coefficient, high electron mobility, and low charge carrier thermal generation rate. 1,5,17 The PbSe is a direct bandgap material, which shows a narrow bandgap of around 0.27 eV at room temperature (RT). 5,19 The bulk PbSe semiconductor exhibits some crucial characteristics such as crystal structure of cubic form, large exciton Bohr radius, small effective masses for both electrons and holes, and a large dielectric constant.…”

“…1,5,17 The PbSe is a direct bandgap material, which shows a narrow bandgap of around 0.27 eV at room temperature (RT). 5,19 The bulk PbSe semiconductor exhibits some crucial characteristics such as crystal structure of cubic form, large exciton Bohr radius, small effective masses for both electrons and holes, and a large dielectric constant. 19 The large dielectric constant leads to a low exciton binding energy, and thus charges are almost free due to low scattering loss, 37 which inherently favors total photocurrent generation.…”

“…3 With advanced fabrication technology, it is possible to integrate photodetectors with electronic readouts to make detector FPAs, which is now one of the key research focus. 5 Single crystalline or polycrystalline PbSe thin films can be grown on silicon substrates to fabricate FPA because it allows large area uniformity and easy integration with Si wafer. 3 However, it faces a fundamental challenge of high dislocation density because of a large mismatch in lattice constant and thermal expansion coefficient between PbSe film and Si wafers.…”