Green/yellow luminescence from highly strained BeZnCdSe quantum wells grown by molecular beam epitaxy

Abstract

We have investigated the luminescent properties of highly strained BeZnCdSe quantum wells (QWs). Single‐QW structures were grown on (001) n‐GaAs substrates by molecular beam epitaxy with various Cd beam pressures. High‐resolution X‐ray diffraction measurements revealed that the lattice mismatch between the BeZnCdSe QW and the GaAs substrate changed from 2.1% to 3.0% as the Cd beam pressure was increased. The photoluminescence (PL) spectra showed that the peak wavelength was nearly proportional to the lattice mismatch for each sample. Fluorescence microscopy measurements revealed that the PL images of all the samples showed a similar luminescence distribution, but the images of samples having the lattice mismatch of 2.8% and 3.0% showed some dark lines. These results suggest that flat QW layers were formed in all the samples, but the lattice relaxation of the QW layer occurred in highly strained samples with lattice mismatches greater than 2.8%. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Continuous-wave operation of green/yellow laser diodes based on BeZnCdSe quantum wells

“…BeZnCdSe with higher Cd alloy composition exhibits higher compressive strain, concerning about a possibility of degradation in crystal quality due to lattice relaxation. Effect on high Cd incorporation to crystal quality of the active layer is examined by photoluminescence (PL) measurement for single quantum well (SQW) samples, where laser for excitation wavelength is 405 nm and the input power is 1mW [16]. A sample structure consists of a 1-μm-thick BeMgZnSe buffer layer, a 0.1 μm-thick BeZnSe waveguide layer, a 7-nm-thick BeZnCdSe active layer, a 0.1-μm-thick BeZnSe waveguide layer, and a 0.15-μm-thick BeMgZnSe capping layer.…”

Low-threshold-current yellow BeZnCdSe quantum-well ridge-waveguide laser diodes under continuous-wave room-temperature operation

“…8) It has been investigated that BeZnCdSe QWs with a small lattice mismatch can be promising candidates for use as the active layer in yellow laser diodes. 9) Good crystalline quality of QWs with a high Cd content can be realized under careful growth conditions. The room-temperature cw operation of BeZnCdSe single-quantum-well (SQW) green LDs has already been realized 10) and a gain-guided green laser with an output power of 50 mW was reported.…”