Doping studies of InSb and InAs1-xSbx prepared by metal organic chemical vapor deposition

InAs1-xSbx/InSb strained-layer superlattices (SLS's) have been proposed for use as long wavelength detectors in the 8-12 micron range. Bandgap reduction is achieved when the alloy is under tension. The preparation of crack- and dislocation-free InAs1-xSbx/InSb SLS's was achieved by metal-organic chemical vapor deposition on compositionally graded InAs1-xSbx buffer layers. Infrared response has been demonstrated for these SLS's in the 8-12 μm region. Fabrication of a photodiode is an important step in the development of a new infrared material. The preparation of a grown p-n junction diode requires controlled doping of the InAs1-xSbchi/InSb SLS. In order to controllably dope these SLS's it is necessary to find suitable dopant sources. Several n- and p-type dopant sources have been investigated. These include diethylzinc, dimethylcadmium, hydrogen selenide, silane, dimethyltellurium, and diethyltellurium. The authors discuss how the results of these doping experiments have allowed them to control the doping levels in the InAs1-xSbx/InSb SLS's with enough precision to produce the first InAsSb photodetector by MOCVD