Left Outer Join Using Linq

Question

List<Employee> employees = new List<Employee>();

employees.Add(new Employee { empId = 1, empName = "Emp1", deptId = 1 });

employees.Add(new Employee { empId = 2, empName = "Emp2", deptId = 2 });

employees.Add(new Employee { empId = 3, empName = "Emp3", deptId = 1 });

employees.Add(new Employee { empId = 4, empName = "Emp4", deptId = 3 });

employees.Add(new Employee { empId = 5, empName = "Emp5", deptId = 4 });

 

List<Department> depts = new List<Department>();

depts.Add(new Department() { deptId = 1, deptName = "CSE" });

depts.Add(new Department() { deptId = 2, deptName = "IT" });

depts.Add(new Department() { deptId = 3, deptName = "CIVIL" });

 

I need to Dispaly all the employees with department name, if the departmet is not exists in  need to display null for that employye

i tried with 

var result = (from emp in employees

                       join dept in depts on emp.deptId equals dept.deptId

                      into a

                     from b in a.DefaultIfEmpty(new Department())

                     select new

                    {

                       empId = emp.empId,

                       empName = emp.empName,

                       deptId = b.deptId,

                       department = b.deptName

                    });

but still it is retrunign only 4 Employees whoever having the departments in Departmet table. 

Can any one help in this.