CdHgTe-based nanostructures for photodetectors

Abstract

This paper presents the results of growing quantum wells based on HgTe (HgTe/Cd0.735Hg0.265Te) 16.2 and 21nm thick on substrates of (013) CdTe/ZnTe/GaAs by molecular-beam epitaxy. The composition and thickness of the spacer and of the quantum well were monitored by an ellipsometric technique during growth. Galvanomagnetic studies in a wide range of magnetic fields (1-12T) at temperatures close to that of liquid helium (4.2K) showed that a two-dimensional electron gas is present in the nanostructures and that the levels are quantized. High mobilities were obtained for the two-dimensional electron gas: μe=2×105cm2/(V⋅sec) for an electron density of Ns=1.5×1011cm−2 and μe=5×105cm2/(V⋅sec) for Ns=3.5×1011cm−2. The circular and linear photogalvanic effects were studied in the quantum wells at room temperature in a wide wavelength interval: from the mid-IR (6-16μm) to the terahertz range (100-500μm).