NOVELTY - A self-assembled monolayer (3) comprises tetrahydronaphthalene moiety (I).    USE - Self-assembled monolayer is used for organic electronic device e.g. organic field-effect transistor, thin-film transistor, integrated circuit, logic circuit, capacitor, radio frequency identification tags, devices or components, organic light-emitting diode, organic light-emitting transistor, flat panel display, backlight of display, organic photovoltaic device, organic solar cell, photodiode, laser diode, photoconductor, organic photodetector, electrophotographic device, electrophotographic recording device, organic memory device, sensor device, biosensor, biochip, security marking, security devices, and components or devices for detecting and discriminating deoxyribonucleic acid sequences (all claimed).    ADVANTAGE - The self-assembled monolayer has excellent contact resistance, and channel resistance.    DETAILED DESCRIPTION - A self-assembled monolayer comprises tetrahydronaphthalene moiety of formula (I).    X1=-CH2-, -CF2-, or aryl-R5;    X2=-CH2-, -CF2 or -C(=O)-;    X3=X2 or N-R6;    X4=X2 or N-R7;    R1,R6=optionally H, F, or methyl or ethyl (both optionally substituted by F), -(CC)a-(Ar1)b-(CC)c-(R8)d-X5-;    Ar1=p-phenylene optionally substituted by N;    R8=-CH2 or CF2;    X5=Xa, Xa-Xb-, -C(=Xa)-Xb-, -Xa-XbO3-, -PO2H or -PO3H-;    Xa,Xb=S or Se;    a,b,c,d=0,1 or 2;    R2-R7=H, F, or methyl or ethyl (both optionally substituted by F);and    or 2 or more R2-R5,R7=aliphatic or aromatic ring having 6-24 aromatic carbon atoms.    INDEPENDENT CLAIMS are included for the following:    (1) organic electronic device, which consists of self-assembled monolayer; and    (2) formation of self-assembled monolayer, which involves providing a metal surface or metal oxide surface, and applying 1 or more tetrahydronaphthalene compound (I) as precursor to metal surface or metal oxide surface and forming self-assembled monolayer on metal surface or metal oxide surface.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of organic field-effect transistor.    Substrate (1)    Source and drain electrode (2)    Self-assembled monolayer (3)    Layer of organic semiconducting material (4)    Dielectric material layer (5)