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I am currently studying the textbook Physics of Photonics Devices, Second Edition, by Shun Lien Chuang. In a section discussing The Invention of Semiconductor Lasers, the author says the following:

At the Solid State Device Research Conference in July 1962, an MIT Lincoln Laboratory group and RCA Laboratories reported extremely high efficiency (85% to 100%) electroluminescence from GaAs diffused junction diodes. Semiconductor lasers were invented during September to October 1962 by four groups within 30 days [9-12] (see the review article by Dupuis in Ref. 13). They were led by Robert N. Hall of General Electric Research Development Center, Schenectady, New York; Nick Holonyak Jr. of General Electric, Syracuse, New York; Marshall I. Nathan of the IBM Research Laboratory, Yorktown Heights, New York; and Robert Rediker of the MIT Lincoln Laboratory, Lexington, Massachusetts. Among the four groups, only Holonyak's laser diodes and light-emitting diodes (LEDs) were created from single-crystal GaAs$_{x}$P$_{1 - x}$ alloy material grown by vapor-phase transport and were the only devices emitting in the visible region.

I had already read about vapor-phase deposition in a textbook on MEMS (microelectromechanical systems), but I was not familiar with vapor-phase transport. Reading about these two methods, they sound very similar, and I'm unsure if they're just different names for the same thing, or whether there is some difference between them. I would greatly appreciate it if someone would please take the time to explain the difference between, if any.

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The paper of interest is C.M. Wolfe et al., "Growth and Dislocation Structure of Single-Crystal Ga(As$_{1-x}$P$_{x}$)", Journal of Applied Physics 36(12) 3790 (1965).

The key paragraph is:

The GaAsP of this investigation has been prepared by a closed-tube method utilizing a quartz ampoule which is cleaned and baked-out under vacuum near the softening point of quartz. The halide is introduced by subliming a metallic halide, such as PbCI2, PbI2, NH4CI, NH4I, etc.,ro into the reaction vessel. Typically, 2.2 g of source GaAs and GaP, 4-8 mg of excess P, 40-160 mg of halide, and a dopant are placed in an 8-cm$^{3}$ ampoule as in Fig. 1. This vessel is then evacuated to 10$^{-6}$ Torr, sealed, and placed in a single-zone furnace at 950°C with a gradient of 5°-15° along the tube. Commercially available GaAs is used with GaP grown from high-purity elements by a method previously described.

So, yes, it is a vapor deposition technique, but uses a thermal gradient to evaporate from one place and redeposit in another place, controlled by the temperature.

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