We have explored an effect of the interface resistance of Fe3Si/n(+) -Ge Schottky-tunnel contacts on spin accumulation created electrically in n-Ge. Using the Schottky-tunnel contacts with a relatively high interface resistance, we can clearly detect spin-accumulation signals in n-Ge even at room temperature, meaning that the use of highly resistive Schottky tunnel contacts is effective to electrically create large spin accumulation. Since such highly resistive source and drain electrodes are not available for next-generation Ge-based spintronic applications with ultra-low power consumption, the development of highly spin-polarized spin injectors such as half-metallic materials is essential from now on. (c) 2013 Elsevier B.V. All rights reserved.