Photoelectrical properties of TlGaSe2 single crystals

• Temperature dependent spectral distribution of photocurrent is determined.
• Spectral distribution of the photocurrent with scan direction is determined.
• Spectral distribution of photocurrent with successive measurement is determined.
• Effect of pre-illumination on photocurrent is determined.
• Variation of photocurrent with bias voltage is determined.

The spectral distribution of photocurrent (PC) of TlGaSe2 single crystals in the range of wavelengths between 500 nm and 700 nm possesses a single maximum at 2.04 eV corresponds to the direct energy band gap of this crystal. The PC is enhanced dramatically by pre-illuminations at low temperatures with band gap light. The temperature dependence of PC of the sample investigated in the temperature range from 80 K to 300 K at constant heating rate shows that the overlapping peaks in the PC spectrum are direct reflection of the Thermally Stimulated Current (TSC) associated with the several trapping levels. The PC response is strongly dependent on the degree of occupancy of traps. The wavelength at the maximum of the PC spectrum is found to be dependent on the wavelength scan direction being up or down. The ferroelectric phase transitions of TlGaSe2 are detected at ∼108 K and ∼118 K in the PC spectrum.

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