Effect of doping and counterdoping on high-pressure phase transitions of silicon

Abstract

The influence of dopants and counterdopants on high-pressure phase transitions of silicon was investigated by high-pressure Raman microscopy. A small amount of dopants were found to dramatically influence the high pressure stability of silicon. The combination of doping and counterdoping provides an effective way to manipulate the critical pressures of the phase transitions, which offers unique insights on atomic mechanisms of high pressure phase transitions of Si.

In situobservation of the indentation-induced phase transformation of silicon thin films

“…22 The region of preserved dc structure would be exposed to very large compressive stresses during loading, and hence the mode of Si-I would be expected to shift to significantly higher frequencies. 22,53,55 However, the frequency of the mode changed only marginally with increasing pressure in this study [see Fig. 6(a)].…”

“…The primary phase transformation of Si is usually characterized by a complete disappearance of the Raman mode of the Si-I phase. 18,53 In this paper, a weak signal of this mode is detected through the in situ experiments (see Fig. 5).…”

“…After complete unloading, the recorded Raman spectrum was very similar to spectra recorded on residual indentation imprints in bulk Si samples, as shown in other studies. 14,52,53 The force at which the abrupt change was observed in the spectrum on unloading was in proximity to the discontinuity (so called "pop-out") in the force-displacement curve (see Fig. 4).…”

“…It was assumed that both phases were present in the deformation zone, as recent simulations predict the concurrent transformation of the Si-I phase to β-tin and bct5 structures during indentation loading, 25,[32][33][34][35] The dc Expt. by Guo et al 53 Expt. by Mernagh et al 55 Expt.…”