GROWTH OF HgSe BY ELECTROCHEMICAL ATOMIC LAYER EPITAXY (EC-ALE)

摘要

The growth of HgSe using electrochemical atomic-layer epitaxy (EC-ALE) is reported. EC-ALE takes advantage of underpotential deposition (UPD). UPD is the deposition of a surface limited amount (an atomic layer) of an element at a potential prior to that needed to deposit the bulk element. To form a thin film of a compound--one atomic layer at a time using EC-ALE, a cycle is used where different solutions are used for each element, and atomic layers of each element are deposited sequentially at their underpotentials This defines a cycle, and the cycle is repeated to grow thin films. HgSe thin films were formed on gold substrates using a solution with Hg~(+2) complexed with EDTA and a solution of SeO_2. XRD analysis suggested a preferential (111) texture of the deposits, cubic (zincblende) and with an average grain size of 42.5 nm. Electron Probe Microanalysis (EPMA) showed the deposits as near stoichiometric but a little rich in selenium. Fourier Transform Infrared spectroscopy (FTIR) reflection absorption measurements showed two band gaps of 0.42 eV and 0.88 eV.