Remarkable effects of uniaxial stress on the far-infrared laser emission inp-type Ge

Abstract

The influence of [112] compressive stress on the inter-valence-band laser emission from a p-type Ge crystal containing the acceptor concentration $N_a$≃6×${10}^{13}$ ${\mathrm{cm}}^{\mathrm{-}3}$ is studied. In the absence of stress, the laser emission is classified to the longer-wavelength oscillation (λ≳170 μm) in lower electric fields (E≲800 V/cm) and the shorter-wavelength oscillation (λ≲120 μm) in higher electric fields (E≳800 V/cm). At stress magnitudes of 300±70 and 450±80 kg/${\mathrm{cm}}^2$, the electric field range for the laser oscillation is significantly extended to lower fields, and the intensity of the laser emission in the lower electric fields (E≲800 V/cm) increases by a factor of 10–${10}^3$. Further, at stress magnitude 450±80 kg/${\mathrm{cm}}^2$, new emission lines appear in the intermediate range of λ (120–170 μm), where the oscillation is missing in zero stress. The experimental results are interpreted in terms of the reduction of the rate of inter-valence-band impurity scattering under uniaxial stress.