NOVELTY - A metal semiconductor particle of average particle diameter 10 nm or less, and a specific metal atom complex, are contacted with a solvent of moisture content 10 wt.% or less, to obtain processed metal semiconductor particle.    USE - For manufacture of metal oxide semiconductor electrode used for photoelectric conversion cell (both claimed) of dye sensitizing solar cells, and solar power generation solar cells such as single crystal silicon solar cell, and amorphous silicon solar cell. Processed metal semiconductor particles are also used as photocatalyst.    ADVANTAGE - Metal oxide semiconductor paste having excellent dispersibility of fine particle metal oxide semiconductor, is provided. The paste has excellent stability, and film formability.    DETAILED DESCRIPTION - A metal semiconductor particle of average particle diameter 10 nm or less, and a metal atom complex, are contacted with a solvent of moisture content 10 wt.% or less. The metal atom complex has partial structure of formula (1).    M=1-6 valent metal atom;    A,B=oxygen, nitrogen, phosphorus or sulfur;and    X=bivalent organic residue.    The arrow shows coordinate bond or ionic bond from A and B to M. INDEPENDENT CLAIMS are included for the following:    (1) metal oxide semiconductor paste which contains a solvent and processed metal semiconductor particle;    (2) metal oxide semiconductor electrode formed by applying the paste into a film on a transparent electrode base material;    (3) manufacture of metal oxide semiconductor electrode having a metal oxide porous layer (1); and    (4) photoelectric conversion cell which comprises the metal oxide semiconductor, electrolyte and electroconductive counter electrode.    DESCRIPTION OF DRAWING(S) - The figure shows the model of photoelectric conversion cell. (Drawing includes non-English language text).    metal oxide semiconductor porous layer (1)    electrolytic solution layer (2)    transparent electrode layer (3)    platinum electrode layer (4)    transparent electrode (5)    spacer (6)    conductive wire (10)