Terahertz Emission Mechanisms in III–V Semiconductors …
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for creating diffusion current. Hence, decreasing the bandgap by incorporating more
and more Bi makes the photo–Dember effect increasingly favorable (Fig. 5).
We reported such a transition happening somewhere between x ~ 0.5% and 1.4%
Bi [45]. In the study, all the samples in the set (0 ≤ x ≤ 3.1%) had inherited
p-type doping associated with Bi incorporation. The THz pulses showed opposite
polarity between 0.5 and 1.4% due to a crossover in the emission mechanism from
Fig. 5 THz emission characteristics of (100) GaA 1−x Bi x epilayers observed in reference [45]. (a)
Comparison of THz pulses obtained from epilayers of varying Bi content under similar experimental
conditions. One could see the polarity reversal in THz emission between x ≈ 0.5 and 1.4%. (b)
Trends in THz emission with varying Bi content and its comparison to the theoretical prediction in
reference [46]. (c) The broadband emission spectrum from bismide alloys
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for creating diffusion current. Hence, decreasing the bandgap by incorporating more
and more Bi makes the photo–Dember effect increasingly favorable (Fig. 5).
We reported such a transition happening somewhere between x ~ 0.5% and 1.4%
Bi [45]. In the study, all the samples in the set (0 ≤ x ≤ 3.1%) had inherited
p-type doping associated with Bi incorporation. The THz pulses showed opposite
polarity between 0.5 and 1.4% due to a crossover in the emission mechanism from
Fig. 5 THz emission characteristics of (100) GaA 1−x Bi x epilayers observed in reference [45]. (a)
Comparison of THz pulses obtained from epilayers of varying Bi content under similar experimental
conditions. One could see the polarity reversal in THz emission between x ≈ 0.5 and 1.4%. (b)
Trends in THz emission with varying Bi content and its comparison to the theoretical prediction in
reference [46]. (c) The broadband emission spectrum from bismide alloys