Molecular beam epitaxy of p‐type ZnSTe:N and p–n‐junction light emitting diodes

Abstract

p‐type doping of ZnS1–xTex alloy with N acceptors has been studied with an idea that an upward shift of the valence band maximum due to Te incorporation could improve p‐type doping efficiency. The resistivity was found to be less than 100 Ωcm for the layers with 0.2 < x < 0.3, which are suggested to be p‐type from the currentvoltage (I – V) characteristic and the electron‐beam induced current. For further characterization, ZnSTe:N/n‐ZnS diode structures have been fabricated. It was found that the diode exhibits clear rectification in I – V characteristic, and blue‐green electroluminescence probably due to hole injection from the ZnSTe:N layer into the n‐ZnS layer. These results indicate p‐type conduction in ZnSTe:N, and thus the light‐emitting diode operation in the ZnS‐based pn‐junctions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Molecular Beam Epitaxy and p-type Doping of ZnMgSTe Quaternary Alloys

“…ZnMgSTe layers were grown by a MBE system designed for sulfide growth [4,5] using metal Zn, Te (Osaka Asahi Metal), and Mg (Furuuchi Chemical), and elemental S (Furukawa Denshi) as source materials. In this system, ZnS is usually grown at a substrate temperature of 275 These growth conditions had been obtained in our previous study on ZnSTe ternary alloy growth [1,2], and were also used in this study. Composition of the grown films was evaluated by electron probe micro-analysis (EPMA).…”

“…Thus substituting a part of S in ZnS with Te causes VBM to move upward and seems to make p-type conversion easier. Actually, we have previously reported p-type conduction in ZnS 1−x Te x :N layers in the range of 0.1 < x < 0.3, and the operation of pn-junction light-emitting diodes [1,2]. With the addition of Te into ZnS, however, the bandgap decreases.…”

“…Note the lowest VBM of ZnS among zincblende-structured semiconductors (see Ref. [1] and references therein).…”

ZnSTe coherently grown onto GaP substrates by molecular beam epitaxy using ZnS buffer layers

“…It has also been known, however, that achieving p‐type conduction in ZnS is very difficult. We have previously reported p‐type conduction in ZnSTe:N layers in the range of , and the operation of pn‐junction light‐emitting diodes . The properties of the p‐type layers, however, were not satisfactory for practical applications, e.g., the typical resistivity of cm was not low enough and the photoluminescence intensity was very weak.…”