“…It has promoted the development of information storage, magnetic sensing and other fields. Comparing with the magnetic materials, the MR effect on the non-magnetic semiconductor materials such as Si [3,[9][10][11][12][13][14][15], GaAs [13,16,17] and Ge [18][19][20][21][22] shows a comparably large MR value. However, due to the variety of non-magnetic semiconductor materials and the difference in the structures of the devices, the physical mechanisms of MR effects are various, such as the space charge effect model [3,11,14,18,[23][24][25][26], the diode-assisted geometric enhancement model [16,19,27], the photo inducedassisted enhancement model [13], the carrier recombination model [28][29][30], and avalanche breakdown model [12,15,17,[31][32][33], and so forth.…”