Molecular beam epitaxial growth and characterization of ZnSe on (001) ZnSe substrates and its application in light-emitting diodes

Abstract

ZnSe substrates grown by the seeded chemical vapour transport method have been used for homoepitaxial growth by molecular beam epitaxy (MBE). Special attention is paid to mechanically untreated as-grown (001) surfaces and a novel chemical and thermal etching procedure suitable for MBE substrate preparation is proposed. The homoepitaxial layers exhibit excellent optical and structural quality confirmed by low-temperature photoluminescence measurements and high-resolution x-ray diffraction. Light-emitting diodes (LEDs) with five Cd 0.2 Zn 0.8 Se quantum wells and ZnSe as barrier material have been fabricated. Using photolithographic and wet-etching techniques, electrical contacts were realized from the top of the devices. The LEDs possess good rectifying properties at room temperature and emit bright green light at 511 nm with a full width at half maximum of only 65 meV. The external quantum efficiency of the devices (up to 0.8%) is discussed in detail.

Surface treatment of znse substrate and homoepitaxy of znse

“…Saturated K.2Cr207 and KMnO 4 based solutions have both been reported to be suitable chemical etchants for removing surface damage induced by polishing. 8,11 The properties of these two etchants have been investigated in detail during this study. Chemical etching using a I~Cr~O 7 based solution composed of saturated K2Cr207 (granular-type), H20, and H2SO 4 was carried out at room temperature.…”

Study of Filamentation Threshold in Zinc Selenide

“…We explore this threshold by progressively changing the input wavelength used for laser filamentation in a Zinc Selenide (ZnSe) crystal. By shifting the wavelength from 800 nm ( 0 1.55 hv eV = ) to 2.4 µm ( 0 0.52 hv eV = ) we explore the range of multi-photon ionization from two-photon to six-photon utilizing the fact that, 2.67 22,23]. The use of ZnSe is very convenient since the dispersion regime does not change over this wavelength range [24].…”

Homoepitaxial Growth of ZnO by Metalorganic Vapor Phase Epitaxy

“…Homoepitaxial technique is considered to be one of the good choices for obtaining high quality layers, for instance, in the case of ZnSe growth [9]. However, it is also reported that the surface treatments of substrates, namely surface conditions of the substrates, strongly effect qualities of the epitaxial layers [10].…”