GSST and applications in optical devices

An apparatus comprising:

• a GexSbySezTem alloy, the GexSbySezTem alloy being reversibly switchable between an amorphous phase and a crystalline phase;
• and
• a heating element, in thermal communication with the GexSbySezTem alloy, to heat the GexSbySezTem alloy in the amorphous phase to a first temperature, thereby causing the GexSbySezTem alloy to transition from the amorphous phase to the crystalline phase, and to heat the GexSbySezTem alloy in the crystalline phase to a second temperature higher than the first temperature and to allow the GexSbySezTem alloy to cool to a third temperature lower than the second temperature, thereby causing the GexSbySezTem alloy to transition from the crystalline phase to the amorphous phase,
• wherein x+y is 0.4 to 0.5, z is 0.1 to 0.54, and x+y+z+m=1.

An apparatus comprising:

• a GexSbySezTem alloy, the GexSbySezTem alloy being reversibly switchable between an amorphous phase and a crystalline phase;
• and
• a heating element, in thermal communication with the GexSbySezTem alloy, to heat the GexSbySezTem alloy in the amorphous phase to a first temperature, thereby causing the GexSbySezTem alloy to transition from the amorphous phase to the crystalline phase, and to heat the GexSbySezTem alloy in the crystalline phase to a second temperature higher than the first temperature and to allow the GexSbySezTem alloy to cool to a third temperature lower than the second temperature, thereby causing the GexSbySezTem alloy to transition from the crystalline phase to the amorphous phase,
• wherein x is 0 to 0.15, y is 0.5 to 0.68, z is 0.05 to 0.3, and x+y+z+m=1.

An apparatus comprising:

• a GexSbySezTem alloy, the GexSbySezTem alloy being reversibly switchable between an amorphous phase and a crystalline phase;
• and
• a heating element, in thermal communication with the GexSbySezTem alloy, to heat the GexSbySezTem alloy in the amorphous phase to a first temperature, thereby causing the GexSbySezTem alloy to transition from the amorphous phase to the crystalline phase, and to heat the GexSbySezTem alloy in the crystalline phase to a second temperature higher than the first temperature and to allow the GexSbySezTem alloy to cool to a third temperature lower than the second temperature, thereby causing the GexSbySezTem alloy to transition from the crystalline phase to the amorphous phase,
• wherein x+y is 0.4 to 0.5, z is 0.4 to 0.54, and x+y+z+m=1.

An apparatus comprising:

• a GexSbySezTem alloy, the GexSbySezTem alloy being reversibly switchable between an amorphous phase and a crystalline phase;
• and
• a heating element, in thermal communication with the GexSbySezTem alloy, to heat the GexSbySezTem alloy in the amorphous phase to a first temperature, thereby causing the GexSbySezTem alloy to transition from the amorphous phase to the crystalline phase, and to heat the GexSbySezTem alloy in the crystalline phase to a second temperature higher than the first temperature and to allow the GexSbySezTem alloy to cool to a third temperature lower than the second temperature, thereby causing the GexSbySezTem alloy to transition from the crystalline phase to the amorphous phase,
• wherein x is 0.2, y is 0.2, z is 0.4 to 0.5, and x+y+z+m=1.

An apparatus comprising:

• a GexSbySezTem alloy, x+y being about 0.4 to about 0.5, z being about 0.1 to 0.54, and x y z m=1, the GexSbySezTem alloy being reversibly switchable between an amorphous phase and a crystalline phase;
• and
• a heating element, in thermal communication with the GexSbySezTem alloy, to heat the GexSbySezTem alloy in the amorphous phase to a first temperature greater than a phase transition temperature and less than 100° C. higher than the phase transition temperature, thereby causing the GexSbySezTem alloy to transition from the amorphous phase to the crystalline phase, and to heat the GexSbySezTem alloy in the crystalline phase to a second temperature higher than the first temperature and greater than 450° C. and to allow the GexSbySezTem alloy to cool to a third temperature lower than the second temperature, thereby causing the GexSbySezTem alloy to transition from the crystalline phase to the amorphous phase,
• wherein the refractive index of the GexSbySezTem alloy in the crystalline phase is greater than the refractive index of the GexSbySezTem alloy in the amorphous phase by at least 1 over a spectral range greater than 1000 nm.