Abstract

Blue-green laser diodes have been fabricated in the ZnSSe/CdZnSe quantum well system using structures grown on GaAs substrates in a dual-chamber MBE system. Short-lived room temperature CW operation has been achieved at a wavelength of 515nm with a threshold current density of 580Acm⁻² and threshold voltage of 7V for a stripe-contact device 12μm × 1000μm with coated facets (90%/60%). The device had 1μm thick MgZnSSe optical confinement layers doped n = 8×10¹⁷cm⁻³ and 8×10¹⁶cm⁻³ respectively, ZnSSe waveguide core of total width 0.2 μm, with a centrally located 7nm wide CdZnSe quantum well. The structure was grown on an n-type substrate and was mounted p-side up. To reduce the operating voltage the devices used a new Te/Pd/Pt/Au contact technology and a ZnSe top contact layer grown by migration enhanced epitaxy. Studies of inverted (n on p) structures with GalnP and AlGaAs buffer layers, intended to reduce the internal barrier height at the Zn/Se heterojunction, showed these structures to have high forward voltages. Consequently only pulsed operation of these inverted lasers up to 250K was possible, with a threshold current of 600Acm⁻².

© 1998 IEEE