Technical details: 

- radiation sources: 300 W Xenon  arc lamp (Oriel); 100 W tungsten lamp (Narva)
- monochromators: Cornerstone 130 (Oriel Instruments); H20 UV (Jobin Yvon)
- photoconductivity cell (in which sample is mounted and irradiated): cryostat VPF-100 (Janis) with  cryogenic temperature controller model 325 (Lake Shore)
- oil-free turbo pump station TS-75-D (Janis) for pumping into cryostat vacuum space
- regulated DC power supply:  GPR-30H10D (300V/1A Gw Instek)

- instruments for signal measurements: DMM 4050 digital multi meter (Tektronix); Cary 401 electrometer (Varian); picoammeter model 6485 (Keithley)