Tris(8-hydroxyquinolinato) aluminium (Alq 3 based top-gate-type organic light emitting-transistors (OLETs) have been fabricated by using a simple solution process. The OLET consists of a bulk layer of indium-tin oxide (ITO) and hole injection layer of poly(2,3-dihydrothieno-1,4-dioxin)poly(styrenesulfonate) (PEDOT:PSS) as an anode (source), organic electroluminescent layer of Alq 3 and aluminium (Al) as cathode (drain) and gate. A Current-voltage-luminance (J-V-L) characteristic of the OLETs shows that the current density is depended on polarity of gate bias. Initial internal electric field contributes to the charge diffusion between gate and cathode channel. A vice versa characteristic observed for luminance at cathode-anode and gate-anode channels.