Incident Angle Dependence of the Waveform of the Polarization-Sensitive Photoresponse in CuSe/Se Thin Film

Abstract

The results of studying the waveforms of longitudinal and transverse photocurrent pulses generated in thin, semitransparent CuSe/Se films as a function of the angle of incidence (α) of a femtosecond laser beam at linear and circular polarizations are presented. It has been established that the durations of unipolar longitudinal photocurrent pulses at linear and circular polarizations of laser pumping do not depend on the angle α. It is shown that the evolution of the temporal profile of the helicity-sensitive transverse photocurrent with a change in α strongly depends on polarization. At linear polarization, the shape of the unipolar pulses remains virtually constant; however, at circular polarization, the generation of unipolar and bipolar pulses is possible, with the waveforms strongly depending on the angle α. The influence of the incidence angle on the waveforms of transverse photocurrent pulses is explained by the transformation of linear and circular polarization into an elliptical upon the refraction of light at the air/semitransparent film interface and by the interplay of photocurrents arising due to linear and circular surface photogalvanic effects in the film. The presented findings can be utilized to develop polarization and incidence angle-sensitive photovoltaic devices.

Special Issue on New Trends in Nonlinear Optics in Nanostructures and Plasmonics

“…In [9], the generation of nanosecond photocurrent pulses due to the surface photogalvanic effect (the second-order nonlinear optical phenomenon) was studied in thin semitransparent CuSe/Se films as a function of the angle of incidence and polarization of exciting femtosecond laser pulses at 795 nm. It was found that the evolution of the temporal profile of the helicity-sensitive transverse photocurrent with a change in incident angle strongly depends on polarization.…”

Wavelength‐Dependent Photocurrent Generation Efficiency in the Carbon Nanowall Films

“…However, we have recently observed SPGE photocurrent generation in thin CuSe and CuSe/Se films upon excitation by femtosecond laser pulses. [ 48,49 ] Meanwhile, according to, [ 25,40,41 ] in the generation of surface photocurrent in the metal and metal–semiconductor nanocomposite films, PDE and SPGE manifest simultaneously. In contrast to volumetric metal samples, [ 25 ] the SPGE and PDE signals in the films with moderate sheet resistance are significant and can be observed at room temperature.…”