Against the problem that the present instruments for testing the optical and electrical characteristics of the LED epitaxial wafers or chips always adopt current injection method,and have many disadvantages such as the complexity,high cost,low efficiency and the microscratches or metal contamination on the wafers of chips,etc.,we propose a contactless method based on photoluminescence(PC).Determining the relationship between photoluminescence and electroluminescence,and that between optical and ...