Low-temperature GaSb bolometer for non-equilibrium phonon pulse detection

Abstract

We report on the first use of undoped bulk-grown p-type GaSb as a low-temperature detector in composite bolometers for the detection of non-equilibrium phonons. In the ohmic regime, the detector's low-temperature resistivity measurements are consistent with the Mott variable-range hopping conduction characterized by ln R(T)∝exp (T0/T)1/4 with a temperature coefficient of (-0.42-3.46ln T)-1 K-1 in the temperature range 1.4 K⩽T⩽4.2 K. The detector showed a fast response time of approximately 1 µs and excellent reproducibility. In our opinion, the most promising areas of applications are in nuclear spectroscopy (low-energy x-ray and beta-particle detection) for which small-volume detectors can be used and the study of phonon dynamics in 2DEG structures.

Hopping photoconductivity and the effectiveness of phonon detection in GaAs:Zn bolometers

“…The most plausible explanation of this result is that the probability of absorbing the high energy phonons in the tunneling process is much increased, compared to that for thermal phonons, by the presence of photons [9]. Photo-excited carriers that absorb thermal phonons do not have to hop as far to find a state of the correct energy, decreasing therefore the temperature dependence.…”

“…For the R-T measurements, the samples were thoroughly cleaned with organic solvents using a standard procedure [5]. Any oxidized layers present on the sample surface were removed by soaking them in 10% HCl.…”

“…The parameter T 0 in Mott's law is defined by T 0 ¼ b=E F a 3 , where b is a numerical coefficient and a is the wavefunction localization radius [5]. Light introduces the photon energy, hx.…”