1：Experimental Design and Method Selection:

ZnSe nanowires were grown by a simple vapor transport method using a two-zone horizontal furnace. The fused quartz plates were used as substrates. A 10 ?A thick gold layer was evaporated on the substrates as a catalyst. The zinc selenide powder was put into the furnace at the high temperature zone (～1100?C), and the substrates were placed in the low temperature zone about 30 cm downstream from the ZnSe source powder. The Ar carrier gas was kept ?owing (500 sccm) through the furnace during the growth. The growth time was 1 minute after the temperature of the growth-zone became 800?C. After the growth, the substrates were taken from the furnace and cooled down to room temperature.

2：Sample Selection and Data Sources:

The ZnSe nanowires grown on the quartz substrate were observed using a scanning electron microscope (SEM). The crystallinity of the ZnSe nanowires was evaluated by an X-ray di?raction (XRD) technique.

3：List of Experimental Equipment and Materials:

SEM (JSM-6330F, JEOL, Ltd.), XRD (RINT 2100V, Rigaku Co., Ltd.), spectrometer (Horiba-Jobin Yvon iHR320), 50 W halogen lamp (Ushio Co., Ltd.), thermoelectrically cooled photomultiplier tube (Hamamatsu R375), He-Cd laser (Kimmon IK3302R-E), closed-cycle refrigerator cryostat (CryoMini, Iwatani Industrial Gases Corp.).

4：Experimental Procedures and Operational Workflow:

The PT and optical transmittance measurements were performed using a spectrometer, a 50 W halogen lamp, and a thermoelectrically cooled photomultiplier tube. The 325 nm line of a He-Cd laser was used as the pumping light for PT measurements. The optical measurements were carried out on the same system for all temperatures from 15 and 300 K using a closed-cycle refrigerator cryostat.

5：Data Analysis Methods:

The PT spectrum was analyzed using the standard critical point (SCP) model. The temperature dependence of the band-gap energy E0(T) was described by the formula of Varshni and later P¨assler.