One-Dimensional Band-Edge Absorption in a Doped Quantum Wire

Low-temperature photoluminescence-excitation spectra are studied in an $n$-type modulation-doped $T$-shaped single quantum wire with a gate to tune electron densities. With a nondegenerate one-dimensional (1D) electron gas, the band-edge absorption exhibits a sharp peak structure induced by the 1D density of states. When the dense 1D electron gas is degenerate at a low temperature, we observe a Fermi-edge absorption onset without many-body modifications.

Figure 1

Schematic view of $n$-type doped $T$-shaped quantum wire sample.

Figure 2

Experimental (a) and calculated (b) spectra of PL (dotted line) and PLE (solid line) for 1D wire at various temperatures.

Figure 3

Normalized experimental (a) and theoretical (b) spectra of PL (dotted lines) and PLE (solid lines) for 1D quantum wire at various electron densities. $X$ was assigned to excitons and $X^{-}$ to trions.

Figure 4

(a) Peak positions and (b) estimated electron density and corresponding Fermi energy plotted as a function of gate voltage.