You can add template field as follows:
<asp:TemplateField>
<itemtemplate>
<asp:linkbutton runat="server" id="lnkName" text="<%# DataBinder.Eval (Container.DataItem, "PersonNameColumnName") %>" commandname="PersonDetail" commandarguement="DataBinder.Eval (Container.DataItem, "IDColumnName") %>" />
</itemtemplate>
</asp:templatefield>
Then you can handle the row command event of grid. Inside which you can check if command name is "PersonDetail"? If yes then you can bind another grid with details of the person whose id can be retrieved from Command Arguement.