Indium doping of n-type HgCdTe layers grown by organometallic vapor phase epitaxy

Abstract

n‐type doping of mercury cadmium telluride was achieved using trimethylindium as the dopant source. The layers, grown by the alloy growth technique, were doped to ∼5×10¹⁸ cm⁻³. The donor concentration in these layers was found to exhibit a linear dependence on the dopant partial pressure over the carrier concentration range from 5×10¹⁶ to 3×10¹⁸ cm⁻³. Reasonably high electron mobility values were observed in these indium‐doped layers. Typically, layers with a Cd fraction x=0.23, doped to 3.5×10¹⁶ cm⁻³, exhibited a mobility value of 7.5×10⁴ cm²/V s at 40 K. High electron mobility values, measured over the entire doping regime, suggest a high electrical activity of indium in these layers. The optically measured band edge in these indium‐doped layers was observed to shift to higher energy with increasing doping. The band‐edge energy values measured in 1×10¹⁷ and 3×10¹⁸ cm⁻³ doped layers correspond to x=0.23 and x=0.3, respectively. This increase can be due to an increase in the Cd fraction, or to a Burstein–Moss shift of the band edge with doping.