Electrophysical Properties of p-Type Undoped and Arsenic-Doped Hg1 – xCdxTe Epitaxial Layers with x ≈ 0.4 Grown by the MOCVD Method

Resumo

The temperature dependences of the charge-carrier concentration and lifetime of minority carriers in undoped and arsenic-doped p-type Hg_{1 – x}Cd_xTe epitaxial layers with x ≈ 0.4 grown by the MOCVD-IMP (metalorganic chemical vapor deposition–interdiffusion multilayer process) method are studied. It is shown that the temperature dependences of the charge-carrier concentration can be described by a model assuming the presence of one acceptor and one donor level. The ionization energies of acceptors in the undoped and arsenic-doped materials are 14 and 3.6 meV, respectively. It is established that the dominant recombination mechanism in the undoped layers is Shockley–Read–Hall recombination, and after low-temperature equilibrium annealing in mercury vapors (230°C, 24 h), the dominant mechanism is radiative recombination. The fundamental limitation of the lifetime in the arsenic-doped material is caused by the Auger-7 process. Activation annealing (360°C, 2 h) of the doped layers makes it possible to attain the 100% activation of arsenic.