Electrical properties of low-arsenic-doped HgCdTe grown by molecular beam epitaxy

A study of the electrical properties of p-type, low-arsenic-doped Hg1−xCdxTe (x∼0.3, carrier concentration ∼1×10+15 cm−3) suitable for fabrication of high-operating-temperature photodetectors was carried out. The arsenic-doped HgCdTe samples were prepared by molecular beam epitaxy using an elemental arsenic source and were characterized by Hall measurements at 77 K after the samples were subjected to four different arsenic activation annealing schemes with annealing temperatures ranging from 300 to 450 °C. For comparison purpose, a sample doped to low-10+16 cm−3 was also prepared and subjected to the same annealing schemes. Although the four annealing schemes had little influence on the Hall data of the 10+16 cm−3 sample, they had significant impact on the Hall data of the 10+15 cm−3 sample. Furthermore, it was found that the Hall data could not be explained by any scattering mechanisms but could be satisfactorily modeled by a two-layer model in which an n-type skin layer is included.