# Electrical and Optical Properties of Laser-Induced Structural Modifications in PbSe Films
###### Abstract  
PbSe chalcogenide films are widely used as photosensitive elements in gas analysis devices. High absorption in the IR spectrum region and low electrical resistance are important characteristics. Continuous laser radiation exposure of films in the near UV range makes it possible to achieve the desired characteristics, replacing oven heat treatment in the technological process. In the considered laser technology, PbSe films are subjected to photothermal action by a spot of focused radiation in the progressive scanning mode. In this work, changes in the optical and electrical film properties were studied, and the mechanism of structural laser modification was also considered.  
laser modification; PbSe films; optical characteristics; photodarkening mode; photobleaching mode; heat treatment +
Footnote †: journal: Applied Sciences  
In recent years, laser technologies have been resorted to for the thermal processing of semiconductor films, where nanosecond pulses of excimer lasers were first used, before switching to continuous radiation (CW--continuous wave) of semiconductor lasers with wavelengths from 380 to 450 nm (V--violet) and power radiation from 0.2 to 3.0 W [14]. The use of laser technologies has greatly simplified the conditions for modifying films and also made it possible to use commercially available optical elements and laser sources and also reduced the requirements for the safe operation of laser systems. The introduction of new technologies made it possible to study the structure modification under laser irradiation, and the concomitant change in both the electrical and optical film properties has acquired a new meaning [15].  
The authors [16] present a study of photoinduced changes occurring during laser irradiation. Such modifications are one of the simple and environmentally friendly methods that make it possible to control morphological and optical changes in the studied films with minimal surface damage. In addition to the laser modification method ease used to change the optical \(n\) electrical characteristics, the method also leads to bond breaking and rearrangements within the material structure [16]. This leads to a modification of the amorphous material localized structures, which leads to changes in optical properties, such as transmittance, absorption and extinction coefficient, refractive index, and optical band gap [16; 17]. Laser processing made it possible to reduce the film element resistance by several times, which has found wide application as photoelectric sensors [17; 18]. Further study of the structure and properties of laser modification mechanisms of chalcogenide films opens up opportunities for increasing the sensor's photosensitivity in gas analysis, as well as for creating sensors in the various organic liquid microanalysis.  
In the present study, the sample electrical characteristics change was carried out by modifying the PbSe chalcogenide film structure by continuous near-UV laser radiation. A change in the electrical and optical film properties was found by studying samples before and after laser exposure.