INFLUENCE OF IMPURITIES ON BROAD-BAND P-TYPE-GE LASER SPECTRA UNDER UNIAXIAL-STRESS

We have investigated the stimulated emission of a broadband p-type-Ge laser (light- to heavy-hole laser) with uniaxial stress up to 500 bars . The emission spectra can be divided into two ranges, the low- and th e high-frequency ranges. Between these ranges a region without emissio n occurs (emission gap) which is explained by impurity absorption. Thi s emission gap vanishes for stress values larger than 400 bars. The st ructure of the stimulated emission in the low-frequency range is expla ined by impurity absorption lines. The spectral features of the stimul ated emission in the high-frequency range with applied stress suggest that the emission of the p-type-Ge laser is not caused by transitions between the light- and the heavy-hole subbands. Rather, the emission i s generated by optical transitions between Landau levels of the light holes and excited impurity states.