Effect of iso-valency doping with S, Se or Zn dopants on Hg1-xCdxTe mechanical, structural and photoelectric properties is considered. It was revealed that iso-valency doping reduced the etch pit density and increased the microhardness in
Hg1-xCdxTe single crystals. Such doping also improved the photoelectric properties, especially increased the excess
carrier lifetime. Taking into account the value of equilibrium concentration of S, Se and Zn iso-valency dopants in Hg1-xCdxTe single crystals it was concluded that the most suitable iso-valency dopant is Se.
Investigations and comparative analysis of p-to-n type conductivity processes on the identical samples of vacancy doped p-CdxHg1-xTe (x≈0.2) under IBM and anodic oxide annealing and on the identical samples of As-doped p-CdxHg1-xTe (x≈0.22) under IBM and anodic oxide annealing have been carried out. The conversion of type of conductivity has been observed at the considerable depth of the vacancy doped material both under IBM or under anodic oxide annealing while in the case with As-doped material ony under IBM. It was considered that conversion in all these processes was determined by the mercury interstitial diffusion from corresponding mercury diffusion source and recombination with its native acceptors - cationic vacancies (in the first case) or with donor complex formations (in the second one). It has been shown that in the vacancy doped p-CdxHg1-xTe the effective diffusion coefficients for the mercury interstitials that determines the depth of the converted layer are equal each other at equal temperatures either under thermal annealing in the saturated mercury vapour or anodic oxide annealing. It proves the identity of the mercury concentration in the diffusion source. Absence of the conversion under anodic oxide annealing in the As-doped p-CdxHg1-xTe is explained by insufficient Hg concentration in the source and it matches well with necessary condition for donor complex formation as it takes place under IBM.
Bulk Hg0.8Cd0.2Te crystals still are widely used as a base material for manufacturing IR photoreceivers for the 8-14 micrometers wavelengths range. As these purposes need the material with high mobility of electrons and very low concentration of impurities, problems of purity of the components, used for preparation of it, acquire prime significance.
The influence of thermal annealing on electrical properties of p-n structures formed by ion beam milling (IBM) on vacancy doped CdxHg1-xTe (x equals 0.205) single crystals with p (77 K) equals 5.8(DOT)1015 cm-3 was investigated. After IBM of the initial samples the n-type layers were created with the thickness about 10 (mu) and electron concentration of the main part of n-type layers 5(DOT)1014 cm-3. P-n structures were annealed in air at 85, 120 and 160 degree(s)C during 1, 2, and 4 hours. Degradation of the p-n structure after every annealing step was estimated on changes of the Hall coefficient dependence of magnetic field. It was revealed that degradation of the p-n structure took place due to progressive thickness decreasing of n-layer through Hg passing to intersites and vacancy creation. The critical temperature during technology steps is equal about 100 degree(s)C.
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