Significant photoresponsivity enhancement of polycrystalline BaSi2 films formed on heated Si(111) substrates by sputtering

We fabricated approximately 200-nm-thick BaSi2 films on Si(111) substrates at 600 degrees C. The formation of BaSi2 was demonstrated by X-ray diffraction and Raman spectroscopy. A reduction in the electron concentration (n = 2 x 10(16) cm(-3) ) by 3 orders of magnitude compared to that previously reported (n = 7 x 10(19) cm(-3) ) and resultant photoresponsivity enhancement by more than two orders of magnitude were achieved. The photoresponsivity increased with the bias voltage V-bias applied between the top and bottom electrodes, and reached approximately 0.19 A/W at 2.0 eV, room temperature, and |V-bias| = 0.5 V. (C) 2018 The Japan Society of Applied Physics.