TY - JOUR
T1 - Low temperature, postgrowth self-doping of CdTe single crystals due to controlled deviation from stoichiometry
AU - Lyahovitskaya, V.
AU - Chernyak, L.
AU - Greenberg, J.
AU - Kaplan, L.
AU - Cahen, David
PY - 2000/10
Y1 - 2000/10
N2 - Careful analysis of the Cd-Te pressure-temperature-composition phase diagram, shows a deviation of CdTe stoichiometry only in the Te-depletion direction between 450 and 550 °C. Combined control over the semiconductor composition, via intrinsic defects, and over the atmosphere and cooling rate can, therefore, yield a process for intrinsic doping of CdTe at these relatively low temperatures. We present results that support this. Quenching of CdTe, following its annealing in Te atmosphere at 400-550 °C, leads to p-type conductivity with a hole concentration of ∼2 × 1016 cm-3. Slow cooling of the samples, after 550 °C annealing in Te or in vacuum, increases the hole concentration by one order of magnitude, as compared to quenching at the same temperature. We explain this increase by the defect reaction between Te vacancies and Te interstitials. Annealing in Cd at 400-550 °C leads to n-type conductivity with an electron concentration of ∼2×1016 cm-3. Annealing at 450-550 °C in the equilibrium atmosphere, provided by adding CdTe powder, gives n-type material.
AB - Careful analysis of the Cd-Te pressure-temperature-composition phase diagram, shows a deviation of CdTe stoichiometry only in the Te-depletion direction between 450 and 550 °C. Combined control over the semiconductor composition, via intrinsic defects, and over the atmosphere and cooling rate can, therefore, yield a process for intrinsic doping of CdTe at these relatively low temperatures. We present results that support this. Quenching of CdTe, following its annealing in Te atmosphere at 400-550 °C, leads to p-type conductivity with a hole concentration of ∼2 × 1016 cm-3. Slow cooling of the samples, after 550 °C annealing in Te or in vacuum, increases the hole concentration by one order of magnitude, as compared to quenching at the same temperature. We explain this increase by the defect reaction between Te vacancies and Te interstitials. Annealing in Cd at 400-550 °C leads to n-type conductivity with an electron concentration of ∼2×1016 cm-3. Annealing at 450-550 °C in the equilibrium atmosphere, provided by adding CdTe powder, gives n-type material.
UR - http://www.scopus.com/inward/record.url?scp=0347607301&partnerID=8YFLogxK
U2 - 10.1063/1.1308065
DO - 10.1063/1.1308065
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AN - SCOPUS:0347607301
SN - 0021-8979
VL - 88
SP - 3976
EP - 3981
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 7
ER -