Electrical Contacts to p‐ZnSe Based on HgSe and ZnTe

Abstract

Low resistance ohmic contacts to p-ZnSe involving the use of HgSe are studied in detail. HgSe does not form an ohmic contact with p-ZnSe because of a residual valence band offset at the heterojunction of 0.5 to 0.6 eV. Annealing of HgSe/ZnSe : N does not result in an ohmic contact because a large miscibility gap in Hg,-,Zn,Se prevents a Hg-Zn interdiffusion and therefore the formation of a graded heterojunction. The molecular beam epitaxial (MBE) growth of Hg, -,Zn,Se does not circumvent this problem because these epitaxial layers suffer from a compositional phase separation due to spinodal demixing during MBE growth. A significant improvement of HgSe based contacts could be achieved by the use of ZnSe, -,Te,:N transition layers between HgSe and ZnSe : N. Either by abrupt, graded, or multilayer heterojunctions, very low contact resistivities are obtained. The growth of ZnSe, -,Te,: N layers on top of ZnSe: N is shown to reduce the carrier concentration in ZnSe : N by several orders of magnitude. A nitrogen diffusion process is believed to be responsible for this effect.

Blue‐Green ZnSe Laser Diodes for Optoelectronics. Present State at Würzburg University

“…Important for stable operation at 300 K are high quality ohmic contacts to p-ZnSe at the top of the laser structure. Graded superlattices of p-ZnSe/p-ZnTe with a top layer of the semimetal HgSe covered by Au contacts have been used by us [18]. Contact resistivities below R cm2 could be obtained.…”

Biologically based method for the synthesis of Hg–Se nanostructures by Shewanella spp.

“…Recently, research into the synthesis of metal chalcogenides nanoparticles has been paid great attention due to the promising properties for catalysts, infrared detectors, light emitting diodes and electrochemical cells. [1][2][3][4] In particular, nanocrystalline HgSe particles have been synthesized by the reducing reaction of mercury salt and SeCl 4 in the presence of triethanolamine (TEA) as a complexing agent and hydrazine hydrate as a reductant under ultrasonication. 5 The chemical route for the formation of HgSe nanoparticles was also applied for the study of the conductivity behaviour of polyvinyl alcohol-HgSe quantum dot hybrid lms.…”

Interface reactions and electrical properties of metal contacts (Ti, In, Au, W) on p-ZnSe

“…One option for electrical contacts to p-ZnSe pursued in the literature is the reduction of the breakdown voltage of Schottky barriers [1] but the contacts are still clearly nonohmic. Another possibility is the epitaxial introduction of graded layers based on HgSe and ZnTe which allow for a tunnelling transition from the metal into the p-ZnSe [2].…”