Carrier Decay Lifetimes in the Narrow-gap Hg1–xCdxTe at the Interband and Intraband Excitations

The lifetimes of photoconductive decay carriers under interband and intraband excitations are studied in epitaxial layers of narrow-gap Hg1−xCdxTe (x ∼0.2). Samples with large distances (>3 mm) between small-area electrical contacts and small distances (∼10 μm) with largearea contacts (THz antennas) are studied. The lifetimes of decay carriers for intraband and interband excitations are measured and compared. It has been established that, in samples with n-type conductivity, the lifetimes are comparable (in the interval of 40 ns) for both methods of excitation. At the same time, in samples with a small distance between contacts and a large area (bow-tie antennas), contacts make the main contribution to recombination. The elimination of recombination at the contacts leads to a lifetime of ∼10−6 s.