Photoacoustic investigations of shallow acceptors in silicon by a piezoelectric transducer

Photoacoustic (PA) measurements of p-Si single crystals near an optical absorption edge were carried out by using PZT as a detector. A pronounced peak at 1.07 eV appears in addition to the plateau above 1.2 eV. A hole carrier concentration dependence and a compensation effect by thermally generated donors of the PA spectrum are investigated extensively. By considering these results, it is concluded that the observed peak is due to electron transitions involving boron acceptor impurities. Low temperature spectra down to 90 K also support this conclusion.<
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