Stability of nitrogen in ZnSe and its role in the degradation of ZnSe lasers

Abstract

We use density functional theory to examine the stability of defects in p-ZnSe that are formed by a transition of the nitrogen acceptor to the interstitial site. We find that the threefold positive complex of the interstitial nitrogen with the remaining vacancy is considerably more stable than the nitrogen acceptor. The formation of the complex is, however, limited by a kinetic barrier of 1.8 eV for the site transition, and the fact that the charge of the defect must change. The energetic position of the defect in the energy gap is about 2 eV above the valence band edge. This is in agreement with optical degradation experiments which show the formation of a deep defect in the p-doped waveguide with a transition energy of about 2.1 eV and the diffusion of a positively charged species. ͓S0163-1829͑99͒52548-4͔ RAPID COMMUNICATIONS R16 274PRB 60 GUNDEL, ALBERT, NÜ RNBERGER, AND FASCHINGER

Effects of Electric Fields on Cathodoluminescence from II-VI Quantum Well Light Emitting Diodes

“…After 3000s of spot mode electron irradiation with several biasing cycles, the QW intensity dropped by only -30% (C to 0). These bias effects are quite different from those reported by Gundel et al [8] for a ZnCdSe QW-based laser diode, where rapid degradation occurred with zero bias.…”

“…Voltage, V V The present paper describes effects of both forward and reverse bias on CL from a ZnCdMgSe QW-based LED. Results obtained are much more extensive than those reported by Gundel et al [8].…”

“…Understanding how electrical bias affects carrier transport and defect behavior may help in further improvement of performance and lifetimes of QW-based light emitting diodes (LEDs) and laser diodes [8]. Gundel et al [8] studied the influence of reverse bias on degradation of a ZnCdSe QW-based laser diode by photoluminescence.…”

“…Gundel et al [8] studied the influence of reverse bias on degradation of a ZnCdSe QW-based laser diode by photoluminescence. They [8] argued that the observed changes in the degradation rate with bias were caused by the effects of bias fields on diffusion of charged defect complexes from the p-doped waveguide into the QW. Voltage, V V The present paper describes effects of both forward and reverse bias on CL from a ZnCdMgSe QW-based LED.…”

The dynamics of amplified spontaneous emission in CdSe∕ZnSe quantum dots

“…Previous studies [4][5][6] have shown that electrically pumped CdSe / ZnSe quantum dot (QD) lasers usually face several degradation problems mainly caused by the presence of point defects, which diffuse from the p-type doped upper layers into the active region. Optically pumped LDs do not suffer from such degradation and therefore the idea of obtaining an integrated chip containing a CdSe QD laser structure pumped by a InGaN / GaN blue quantum well laser diode looks very promising.…”