Properties of II–VI semiconductor films grown by photoassisted molecular‐beam epitaxy Available to Purchase

We report the successful use of photoassisted molecular‐beam epitaxy for the preparation of p‐type CdTe epilayers and p‐type modulation‐doped HgCdTe multilayers in which arsenic is used as the substitutional dopant. The CdTe:As epilayers were grown at substrate temperatures which ranged from 230 to 180 °C. The resulting CdTe:As layers exhibited room‐temperature hole concentrations ranging from 7×10¹⁵ to 6.2×10¹⁸ cm⁻³, as determined by van der Pauw Hall effect measurements. This highest doping level is nearly two orders of magnitude greater than that obtained for bulk p‐type CdTe. The mobility of the CdTe:As epilayers ranged from 27 to 74 cm²/V s, at room temperature. The arsenic acceptor ionization energy in CdTe:As was found to be ∼58–60 meV using low‐temperature photoluminescence measurements. The modulation‐doped HgCdTe samples exhibited hole concentrations ranging from 5×10¹⁶ to 1×10¹⁸ cm⁻³ and hole mobilities of ∼200–325 cm²/V s at temperatures <200 K.