how to set foregin key in model

Question

hi to all,
Here i want to set foregin key for employee id but while running code first migration i got a error.How to resolve it.
 
MODEL DESCRIPTION:-

        [Required]

        [ForeignKey("Employee_Id")]

        public int Employee_Id { get; set; }

ERROR DESCRIPTION:-
The property 'Employee_Id' cannot be configured as a navigation property. The property must be a valid entity type and the property should have a non-abstract getter and setter. For collection properties the type must implement ICollection where T is a valid entity type.