Abstract

Long wavelength (1.3 or 1.55 μm) lasers have attracted much attention in recent years due to minimum loss in optical fiber communication. However, the conventional InGaAsP-InP system exhibits a relatively low characteristic temperature (T₀) due to its poor electron confinement. A novel material, GaInNAs on GaAs substrate, has been proposed to solve this problem.¹ By using this material, T₀ is expected to be over 150K due to an energy discontinuity of >300meV in the conduction band. Especially, a GaInNAs/GaAs long-wavelength vertical cavity surface emitting laser (VCSEL) is very attractive², since long wavelength GaAs/AlAs distributed Bragg reflectors can be used Recently, 1.3 μm GaInNAs lasers have been demonstrated by gas-source molecular beam epitaxy (GS-MBE) using N-radicals as N source and metal-organic chemical vapor deposition (MOCVD) using dimethylhydrazine (DMHy), respectively. An electrically pumped VCSEL at 1 18 μm has also reported. However, there has been remained a difficulty in nitrogen incorporation with good quality, and the lasers still exhibit a relatively high threshold current density. The crystal quality of GaInNAs quantum wells (QWs) degrade rapidly as increasing nitrogen concentrations due to phase-separation and local strain, even though the amount of average strain in the layer decreases. The optimization of the growth conditions as well as the growth methods are thus crucial in order to achieve good quality of GaInNAs. In this paper, we studied in detail the growth of GaInNAs/GaAs by an ion-removed de plasma assisted MBE Based on the experimental results, a kinetic model taking into account the nitrogen desorption and surface segregation was established to analyze the incorporation behavior of nitrogen. Optimum growth conditions of GalnNAs were obtained and GaInNAs/GaAs QW lasers have been achieved.

© 2000 IEEE