Precise p-type doping of ZnO microwires for electrically-pumped homojunction microlaser diode

Abstract

Low-dimensional ultraviolet electrically pumped lasers have garnered significant attention for their remarkable achievements and broad potential in both industrial and civilian applications. Herein, we demonstrate an electrically pumped microlaser diode by employing p-type Sb-doped ZnO microwire (Sb:ZnO MW) as effective emission layer, gain medium, and cavity. The carefully-fabricated Sb:ZnO MW homojunction microlaser exhibits distinct Fabry-Pérot modes, absolutely suppressed spontaneous emission, a high quality (Q) factor of 1705, and an impressive output power of 24.3 μW. In the device, the p-Sb:ZnO MWs, synthesized via a self-catalysis high temperature process, exhibit genuine and stable p-type characteristic with hole concentration and mobility of 1.15×10¹⁹ cm⁻³ and 17.6 cm² V⁻¹ s⁻¹, respectively. The incorporation of TeO₂ layer with remarkable hole mobility enables effective current injection and strong confinement of the electron-hole recombination and photons within the MW, facilitating the lasing process. Notably, the recombination region expands within the MW as current increases, thus alleviating efficiency droop caused by Auger recombination and enabling higher output power. This design successfully overcomes the final barrier impeding ZnO homojunction electrically pumped lasing devices, paving the way for their practical application in the future.