Quantum-Film, Quantum-Wire, and Quantum-Box Lasers 



Staffs:    Y.Suematsu  S.Arai      M.Asada   Y.Miyamoto   S.Tamura
Students:  K.Kudo      H.Hirayama  K.C.Shin  Y.Nagashima  K.Matsunaga
           T.Kakinuma  M.Tamura    M.Hotta   S.Kurihashi  M.Kumazawa
           H.Arima     R. Ubukata

Ga1-xInxAs/GaInAsP/InP strained-quantum-film, -wire, and -box lasers have been studied both theoretically and experimentally. By introducing tensile-strained quantum-wire (QW) structure into the active layer, room temperature CW operation of GRIN-SCH single-QW lasers with fairly low threshold current was achieved. GaInAs/GaInAsP (strained-) quantum-box (QB) structures were fabricated and obvious 0-dimensional QB size effects were observed.@Temperature dependences of lasing properties were measured and compared with those of quantum-film lasers. Carrier injection process in SCH quantum-film and wire lasers was investigated.

The results obtained in this research are as follows.


  1. Temperature dependence of lasing properties of quasi-quantum-wire lasers were measured and compared with those of quantum-film lasers.

  2. By combining electron beam lithography and ECR dry etching, 20-30nm wide GaInAs/GaInAsP multi-quantum-wire and -box structures with the aspect ratio greater than 6 were realized. Moreover, low damage feature of this fabrication process was confirmed by PL observation.

  3. An emission energy level shift due to obvious 0-dimensional quantum- box effect was observed at 4K with GaInAs/GaInAsP single-layer (strained-) embedded quantum-box structures.

  4. Lasing action of Ga0.67In0.33As/GaInAsP/InP tensile-strained quantum-box laser was demonstrated for the first time. The fabricated QB size is 30nm diameter and 12nm thick with a period of 70nm. The threshold current density was 7.6KA/cm2 at 77K with pulse current injection.

  5. Carrier capture time of SCH-QW-lasers was measured by the spontaneous emission spectra above threshold. Difference between unstrained, tensile-strained, and compressive-strained lasers was obtained.