Magnetoresistance of proton irradiated Si0.97Ge0.03 whiskers

The effects of proton irradiation and high magnetic fields on the magnetoresistance of Si1-xGex (x = 0,03) whiskers in the 4.2-300 K temperature range has been studied. A slight decrease in the electrical resistance of the crystals in the 4.2-40 K temperature range during irradiation with small proton doses and a significant increase in their resistance in the entire investigated temperature range for a dose of 1×1017 p+/cm2 have been found. The ionization energy of the impurity atoms in different magnetic fields has been calculated. It has been revealed that the energy level of the impurity depends on the magnetic field but slightly which in turn indicates a independence of the concentration of holes on the magnetic field. It has been shown that a significant magnetoresistance at all studied temperatures was due to the magnetic field-caused decrease in the mobility of free carriers (holes). It has been found that the concentration of holes depends on magnetic field but a little. Conclusion has been made about a negligible expansion of the band gap in magnetic fields of up to 8 T.