Experimental and theoretical results are given of an investigation of the capacitance behavior with frequency of GaAs injection lasers. It is shown that, for shallow‐bombarded stripe geometry lasers, the zero‐bias capacitance decreases rapidly beyond a certain frequency. This is interpreted in terms of confinement of the low‐level radio frequency current under the stripe at high frequencies. Comparison of the experimental results with the analytically derived expressions provides a measure of the material resistivity adjoining the active region. This inferred material resistivity is shown to be in good agreement with results obtained by more direct measurements. Finally, the general conclusions are also applicable to other optoelectronic devices operating at high frequency, such as light‐emitting diodes.

No abstract

The cw accelerated aging behavior of proton-bombarded stripe geometry lasers fabricated from MBE grown DH wafers have been studied. The laser diodes were formed into a 5-μm-wide shallow proton-irradiated stripe geometry and operated without mirror coatings in dry nitrogen 70 °C ambients at constant power outputs of 2.5 mW and 3.0 mW/mirror. A feasibility demonstration of long lifetimes was obtained for lasers from three selected MBE wafers; where a median lasing lifetime of 8800 h with a standard deviation of 1.5 was found at 70 °C, which projects to a mean laser lifetime ≳106 h at room temperature. After initial aging, long-term degradation rates as low as 0.7 mA/kh for the operating current at 70 °C have been measured. The present results also show that the rate of change of the operating current with aging for MBE diodes is more uniform than for typical LPE diodes fabricated with the same technology. Data are presented for lasers from one of the wafers that show that after 1500 h of 70 °C cw aging, many of the electrooptical characteristics are relatively unchanged.

A statistical study of the self-induced pulsation behavior of cw (AlGa)As double-heterostructure (DH) (having Al0.08Ga0.92 As active layers) proton-bombarded stripe lasers grown by molecular beam epitaxy (MBE) during accelerated aging at elevated (55 or 70 °C) temperatures is made and compared with that of similar lasers grown by liquid-phase epitaxy (LPE). For the 5-μm-stripe, shallow proton-bombarded (proton damage does not reach the active layer) stripe lasers, those fabricated from an MBE DH wafer studied show a significantly higher oscillation frequency (Fosc) of the self-pulsation than those fabricated from LPE DH wafers. It is also shown that by going from 10-μm-stripe and deep proton-bombarded (proton damage penetrates the active layer) to 5-μm-stripe and shallow proton-bombarded stripe lasers, the Fosc are significantly higher even after an initial burn-in at elevated temperatures (55 or 70 °C) for 100 h.

A gain-guided AlGaAs double heterostructure laser which employs a Schottky barrier in conjunction with a p-GaAs etched mesa contact for current isolation has been fabricated. This Schottky barrier restricted structure provides a device whose electrical and optical characteristics are comparable to that of other gain-guided lasers and which is simple to fabricate. Preliminary aging data indicate high reliability of the Schottky barrier restriction.