 stem electron density ～ 1×10 11 cm -2  Gate Voltage （ Vg ） 0.0 ～ 0.8V  wire electron density 0 ～ 4×10 5 cm -1  arm electron density 0 ～ 1.3×10 11 cm -2 Sample

1μm step0.2μm step scan Scan 1 Micro PL measurement with 1μm / 0.2μm step automatic scanning enables us to find the center (blue circle) at every experiments. Photon Energy (eV) Gate Voltage = 0.1V T=5K Stem well excitation with cw Ti:Sa laser (λ=750nm ) 0.2μW 、 ~1μm 2 spot size Reflection geometry Resolution 0.15meV wire trion PL

Scan 2 arm exciton wire trion Gate Voltage = 0.1V check all available aria with ~500μm ( 1.0μm step ) scanning PL continue more than 500μm…

Vg=0.7VVg=0.5V Vg=0.3V Vg=0.1V 0.5μm step scanning with various Gate Voltage ( Vg ) scan 3 Photon Energy (eV) → find the high quality aria (for example : blue arrow) T=5K PL

Gate Voltage dependence Vg = 0V ～ 0.7V (0.05V step) corresponds n 1D = 0 ～ 4×10 5 cm ‐ 1 E FE = 0~1.8meV ① ② ③ ⑤ ④ ① low electron density →1.569eV exciton peak ② trion peak : 2.3meV below exciton peak (trion binding energy) ③ high density →band to band transition 、 electron plasma state ④ Band Gap Renormalization(BGR) ⑤ Fermi Edge Singularity(FES) T=5K PL

Temperature dependence T=50KT=40KT=30K Photon Energy (eV) T=5K ① BGR at every temperature ② ratio of exciton / trion peak become large with temperature ③ FES disappear at high temperature ①①① ① ②② ③ ③

Temperature dependence of Energy shift compare BGR at Gate Voltage 0.2V~0.7V 5K 30K 40K 50K Photon Energy (eV) T (K)BGR(meV) Small BGR at high temperature ①①①①

・ trion peak （ Vg=0.2 ～ 0.3V ） Temperature dependence of FWHM 5K 30K 40K 50K Photon Energy (eV) T (K)FWHM(meV ) 5 ～ ～ ～ ～ 2.3 ・ At high Gate Voltage (Vg=0.4V ～） temperature dependence of FWHM is very small ④④④④

wire HH PLE PL PL & PLE of wire stem LH stem HH arm HH Photon Energy (eV) arm LH PL detection is perpendicular to the laser excitation to improve S/N ratio. Vg = 0.15V T = 5K LH ： light hole HH ： heavy hole excitation detect polarization

0.0V 0.1V 0.15V 0.2V 0.3V 0.4V ① ② ③ ① neutral exciton (exciton) ② charged exciton (trion) ③ FES Photon Energy (eV) Low density PLEPL ③ Gate Voltage 0.0V ～ 0.4V Theoretical work ： M. Takagiwa, T. Ogawa, 2001 density n 1D H L

0.25V 0.35V 0.4V 0.5V 0.6V 0.7V 0.15V ① Fermi Edge ② Band Edge ③？？？ ① ② ③ High density Photon Energy (eV) PLEPL Gate Voltage 0.4V ～ 0.7V electron plasma

 Electron density dependence of PLE varies with the position of the wire. PLE trion→electron plasma Photon Energy [eV] PL and PLE intensity [arb. Uuits] （ PLE ） Vg = 0.3V Vg = 0.35V Vg = 0.4V Vg = 0.45V Vg = 0.5V （ PL ） Vg = 0.15V PLE PL PLE PL PLE PL

 PLE （ Vg=0.15 ） and PL （ Vg=0.12 ） at different position of wire.  Resolution of PL : 0.15meV, PLE : 0.04meV 。  The gap between exciton peaks (or trion peaks) varies with electron density from 0.3meV to 0.5meV. This is probably due to stem well ML fluctuation (theoretical calculation : stem well ML fluctuation is ~0.3meV). High resolution PLE PL and PLE intensity [arb. Uuits] Photon Energy [eV] PLEPL

0.0V 0.02V 0.04V 0.06V 0.08V 0.14V 0.10V 0.12V  Exciton peak shifts with electron density : 3.5meV / V ( blue line ).  FWHM of PL spectrum (corresponds E F ) changes ~ 3.5meV/V.  Trion peak doesn’t shift.  Equation below can be expected. exciton shift PLE trionexciton : exciton : trion

D （ arm well ） / 1D well ① ① ② ② ③ ③ 0.5 wire EFEF （ me V ） EFEF （ me V ） ④④ ① E b wire : E b =2.3meV well : E b =1.4meV ② wire ： blue shift, rapid damping well ： blue shift, broadening ③ trion absor p wire ： no shift, rapid damping well ： blue shift, broadening ④ wire ： large blue shift well : small blue shift begins from trion peak smoothly exciton Absorp. plasma absorp. V. Huard et al. Phys. Rev. Lett. 84 (2000) 187