Lattice-matched heterostructures as Schottky barriers: HgSe/CdSe

Abstract

A novel structure, which is both a lattice-matched heterostructure and a Schottky barrier, is fabricated by epitaxial growth of (111) oriented HgSe on (0001) oriented CdSe. Hydrogen transport CVD is used, with a HgSe source temperature of 420°C and a CdSe substrate temperature of 330°C. Single crystal growth was obtained. Of the two orientations possible for the crystal symmetries involved, only one was observed for a given specimen. The ’’Schottky barrier’’ height for this lattice-matched heterostructure is 0.73±0.02 eV as measured by the photoresponse method. This uncertainty is substantially less than is usual for Schottkies. The magnitude is greater by about one-quarter volt than is achievable with the most electronegative elemental metal, Au, in qualitative agreement with work function arguments.

Major Electronic Transition Shift from Bandgap to Localized Surface Plasmon Resonance in CdxHg1–xSe Alloy Nanocrystals

“…The 67% Cd ratio of CdSe nanocrystal is reduced to 51% in CdHg(1)­Se, and the portion becomes smaller with increased number of mercury precursor addition. Because of the negligible lattice mismatch between zinc blende crystal structures of CdSe and HgSe, the alloy nanocrystal epitaxially grows (or Schottky) . Accordingly, the peaks exhibit no significant shift but become narrower due to the size-growth.…”

“…Because of the negligible lattice mismatch between zinc blende crystal structures of CdSe and HgSe, the alloy nanocrystal epitaxially grows (or Schottky). 25 Accordingly, the peaks exhibit no significant shift but become narrower due to the size-growth. The peaks shown at 25°, 42°, and 49°c orrespond to the (111), (220), and (311) facets of CdSe and HgSe nanocrystals, respectively, and are consistent with the results previously reported.…”

The Metal-Semiconductor Interface

“…Based on W~-arguments or the "common anion" correlations discussed in the next section, one expects HgX to be effectively more electronegative than Au. Studies of CdSeHgSe prepared by chemical vapor deposition (78) show ~b = 0.73 ___0.02 eV, www.annualreviews.org/aronline Annual Reviews which is ~0.24 eV higher than occurs with CdSe-Au. Also noteworthy is the relatively small uncertainty in ~b for this lattice-matched structure.…”

Formation of HgSe Thin Films Using Electrochemical Atomic Layer Epitaxy

“…The work in this group focuses on the development of electrochemical atomic-layer epitaxy ͑EC-ALE͒ for the formation of compound semiconductor thin films. [35][36][37][38] It is the electrochemical analog of atomic layer epitaxy ͑ALE͒ [39][40][41][42] or atomic layer deposition ͑ALD͒, [43][44][45][46][47][48] both of which are gas-or vacuum-based methods for the formation of compounds an atomic layer at a time, using surfacelimited reactions. As noted, UPD is an electrochemical surfacelimited reaction and is used in EC-ALE to promote monolayer-bymonolayer growth, and promote epitaxy.…”