NOVELTY - The method involves manufacturing an n type silicon (Si) layer with impurity deep energy level on a rough surface, and forming a p type semiconductor layer on the n type silicon layer to develop a pn knot with the n type silicon layer. A high temperature annealing treatment is performed for a doped silicon plate formed with the pn knot to activate impurity, and a p type electrode is made on the p type semiconductor layer. An n type electrode is formed on a weak n type silicon substrate, and another n type electrode is formed at a lower surface of the weak n type silicon substrate.    USE - Method for manufacturing a crystalline silicon photovoltaic battery with impurity deep energy level.    ADVANTAGE - The method enables increasing the areas of the p electrode and the n electrode when the pn knot is arranged at a backlight surface, so as to improve the duty factor of a battery, thus enhancing the output of a carrier and reducing the area of the n electrode. The method enables facilitating absorption of high amount of infrared light by silicon, so as to adjust the internal electric field of the battery and cover the n type silicon layer with impurity deep energy level. A photon-activated electrons-electrode hole pair of a region is separated by utilizing the method, thus realizing the output of the photon-activated electrons on the impurity deep energy level and improving the photovoltaic efficiency of the battery.    DETAILED DESCRIPTION - The rough surface is formed by utilizing a chemical corrosion method, where the mixed alkali corrosive liquid of sodium hydroxide (NaOH) and ethanol or ethyl alcohol (C2H5OH) is used to corrode a surface of the silicon substrate in the rough surface or the rough surface is formed by utilizing an ultra-short pulse laser to scan the surface of the silicon substrate in sulfur (S), selenium (Se) or tellurium (Te) element atmosphere. The p electrode and the n electrode are made of aluminum (Al), chromium (Cr), gold (Au), tungsten (W) or titanium (Ti).    DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart illustrating steps involved on a manufacturing method for crystalline silicon photovoltaic battery with impurity deep energy level.'(Drawing includes non-English language text)'