The formation of self-assembled CdSe quantum dots under Stranski-Krastanow (S-K) mode by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) was reported for the first time. The samples were grown directly on GaAs (100) surfaces by LP-MOCVD. DimethylSelenide (DMSe) and DimethylCadmium (DMCd) were used as precursors. The growth pressure was kept at 2.93×10

4

Pa and the growth temperature was 500℃. CdSe with the thickness of about 2 monolayers was grown directly on GaAs (100) surfaces. For the purpose of AFM observation

this uncapped sample was cooled down immediately to room temperature and was monitored under a Digital Instruments Nanoscope Ⅲa system at the same day of growth. The AFM images show that the average diameter

height and density of those self assembled CdSe quantum dots are 50±15nm

13±4nm and 5μm

-2

respectively. And those dots' diameter-height ratio is about 4～5

just the same as those results observed in other Ⅱ-Ⅵ and Ⅲ-Ⅵ compounds which were grown under S-K mode by MBE.