Proposal and verification of a new visible light emitter based on wide band gap II-VI semiconductors

Abstract

We propose a new device structure for obtaining visible light emission from wide band gap semiconductors. This heterojunction structure avoids ohmic contacting problems by using only the doping types which tend to occur naturally in II-VI semiconductors, while using a novel injection scheme to obtain efficient minority carrier injection into the wider band gap semiconductor. To verify this proposal we have fabricated green light emitting structures using n-CdSe and p-ZnTe regions separated by a graded Mg,Cdt -$e injection region. Room temperature electroluminescence spectra from these devices demonstrate the effectiveness of the injection scheme, while the current-voltage characteristics show the merits of avoiding difficult ohmic contacts. We further show how the structure can be extended to blue wavelengths and beyond by opening up the band gap of the ZnTe recombination region with a Mg,,Zn,-,,Te alloy.

Growth and optical characterization of Cd1‐xBexSe and Cd1‐xMgxSe crystals

“…Although there exists a large number of articles on the band-gaps and the excitonic properties of CdSe (see for example Refs. [12][13][14][15]), only a limited number of papers concerning CdMgSe, ZnCdMgSe and CdBeSe compounds have been published [13][14][15][16][17][18][19][20][21][22][23][24].…”

FP-LMTO study of structural, electronic, thermodynamic and optical properties of MgxCd1−x Se alloys

“…These alloys have the possibility of tuning the band gap and lattice constants by varying the Mg concentration. Mg x Cd 1−x Se alloys have attracted great attention because they are promising for the fabrication of full-color visible optical devices due to a large difference in the energy gaps Eg of the binary constituents (CdSe, * E-mail: lttnsameri@yahoo.fr Eg = 1.74 eV; MgSe, Eg = 4.0 eV) [2] To date, only few papers have been reported on the recombination processes in Mg x Cd 1−x Se crystals and the fabrication of green-light-emitting structures using n-CdSe and p-ZnTe regions separated by a graded Mg x Cd 1−x Se injection region [1][2][3][4][5][6][7][8].…”

“…construction of blue-green laser diode operating at room temperature (RT)) [1]. These alloys have the possibility of tuning the band gap and lattice constants by varying the Mg concentration.…”

Minority carrier recombination lifetimes in n-type CdMgSe mixed crystals measured by means of the photothermal infrared radiometry

“…Moreover, Cd 1-x Mg x Se alloy has been successfully applied as graded injector in constructing green−light−emitting structures [6]. The optical, thermal and electrical properties of these crystals were studied in papers [7][8][9].…”