Controlled p-type impurity doping of HgTe-CdTe superlattices during molecular-beam-epitaxial growth

Abstract

We report identification of a reliable p-type impurity dopant that can be used during molecular-beam-epitaxial (MBE) growth of HgTe-CdTe superlattices. Silver doping during the epitaxial growth of (100)-oriented HgTe-CdTe superlattices is shown to yield reproducible hole concentrations in the range of 1016–1018 cm−3. When normalized by the growth rate, the hole concentrations show an exponential dependence on the temperature of the Ag effusion cell. The diffusion of Ag in step-doped junctions was studied by use of secondary-ion mass spectrometry. The diffusion coefficient of Ag at the low MBE growth temperatures was found to be in the range of (1–5)×10−13 cm2/s. These values are comparable to recently reported values in MBE-grown (Hg,Cd)Te alloys and suggest that strain does not produce any new diffusion paths in the superlattices.

Fast and Sensitive Colloidal Quantum Dot Mid-Wave Infrared Photodetectors

“…This gold electrode provided better resistance to thermal cycling and functions as a back reflector to the infrared radiation. For the underlying p-type contact layer, the initial motivation to use Ag 2 Te nanocrystals was inspired by the use of Ag as a p-type dopant in epitaxial HgCdTe. , In addition, the p-type layer acted as an hole transport layer.…”

“…For the underlying p-type contact layer, the initial motivation to use Ag 2 Te nanocrystals was inspired by the use of Ag as a p-type dopant in epitaxial HgCdTe. 8,16 In addition, the p-type layer acted as an hole transport layer. The construction of the HgTe CQD infrared detector is illustrated in Figure 1a.…”

Auger suppression in CdHgTe heterostructure diodes grown by molecular beam epitaxy using silver as acceptor dopant

“…Indium is established as a relatively well-behaved donor in CMT grown by MBE while it has have been more difficult to find a good extrinsic acceptor dopant. In recent years, attention has been focused on arsenic, 3,4 although previously the use of silver [5][6][7][8][9] and lithium 10 has been reported. Arsenic is a slow diffuser, but appears to require complicated growth and/or processing techniques in order to achieve good activation ͑electrical efficiency of dopant͒ in MBE-grown material.…”