INJECTION LASER STUDY.
Quarterly technical rept. no. 3, 1 Dec 63-29 Feb 64.
IBM WATSON RESEARCH CENTER YORKTOWN HEIGHTS N Y
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Mn- and Zn-diffused GaAs negative resistance diodes were switched from the low-current state into the high current, lasing state at 4.2 K. Switching times of the order of 10 to the minus 7th power sec were obtained in the rather small range of excess voltages. These lasers have an anomalously slow variation of the threshold current with temperature below 77 K, a rather sharp fall-off in the emission of radiation associated with Mn centers with increasing temperature, particularly near and above 200 K, and a lack of saturation of the light output in the Mn line when the threshold current is exceeded. The current-voltage characteristic of the double diffused diodes changes from a linear to a quadratic dependence as the current increases. An alternative to the bistability mechanism for a GaAs laser with two regions, only one of which carries appreciable current, was proposed. A series of results for the gain factor and for the loss in a three-layer model of an injection laser is given. A simple formula describing the time delay between the application of a current pulse and the onset of stimulated emission is given. A qualitative estimate of the active region width and of the spontaneous emission lifetime is made, and shows these quantities to be relatively insensitive to temperature and background doping level in zinc-diffused GaAs diodes. A comparison of the properties, preparation, and device applications of InP and GaAs is presented. Author