Physical properties of pulsed-laser-deposited Bi2Se3 and Cu0.125Bi2Se3 thin films studied by Terahertz Time Domain and Femtosecond Pump-Probe Spectroscopy
|關鍵字:||拓樸絕緣體;硒化鉍;摻銅硒化鉍;時間解析;Topological Insulator;Bi2Se3;Cu-doped Bi2Se3|
In this work, we have prepared Bi2Se3 and Cu0.125Bi2Se3 thin films were grown on sapphire(Al2O3)(0001) substrates by pulsed laser deposition(PLD) with various deposition temperatures、pressures and laser pulse energy. We analyzed their crystal structure and thin film quality utilizing X-ray diffraction(XRD). The physical properties in Bi2Se3 and Cu0.125Bi2Se3 thin films with various temperature conditions were studied by terahertz time-domain spectroscopy(THz-TDS) and Hall measurement. Combined with the scanning electron microscopy(SEM)、energy dispersive spectrometer(EDS) and optical pump-probe spectroscopy(OPOP), we discuss the problem of Se vacancies in Cu doping the Bi2Se3 thin films. Phonon dynamics in Bi2Se3 and Cu0.125Bi2Se3 thin films were modified by laser annealing. The dramatic change of the differential transmission spectra (ΔR/R) have been observed when the wavelength of the mid-infrared probe beam is near the minimum plasma edge.