Microcylinder laser structures with diameters ranging from 20 ㎛ to 50 ㎛ based on the high relfectivity whispering gallery modes around the edge of a semiconductor microcylinder is described and a few experimental results are presented. AuZn thermal evaporation, photolithography, and chemically-assisted ion beam etching(CAIBE) are used to achieve the microcylinder laser structure with a GaAs/$Al_{0.2}Ga_{0.8}As$ single quantum well. Whispering gallery modes are demonstrated in the microcylinder laser structure with each diameter using current injection of a few tens milliamp. And a broad peak around 850 nm is observed in spectra at the low current level, which is attributed to conduction-band-to-heavy-hole-band transition. No lasing in the microcylinder laser structure may be due to larger loss by means of the rough sidewall of the microcyliders than gain.
